U.S. patent application number 14/840699 was filed with the patent office on 2015-12-24 for image pickup apparatus and zoom lens used in image pickup apparatus.
The applicant listed for this patent is OLYMPUS CORPORATION. Invention is credited to Hiroshi Kodama, Toshio Takahashi.
Application Number | 20150370049 14/840699 |
Document ID | / |
Family ID | 49946250 |
Filed Date | 2015-12-24 |
United States Patent
Application |
20150370049 |
Kind Code |
A1 |
Takahashi; Toshio ; et
al. |
December 24, 2015 |
Image Pickup Apparatus and Zoom Lens Used in Image Pickup
Apparatus
Abstract
The 1st positive lens unit is located closer to the object side
at the telephoto end than at the wide angle end. The distance
between the 1st negative lens unit and the 1st positive lens unit
is larger at the telephoto end than at the wide angle end. The
distance between the image side lens unit group and the 1st
negative lens unit varies during zooming from the wide angle end to
the telephoto end. The image side lens unit group comprises a 2nd
positive lens unit and a 3rd positive lens unit. The distance
between the 2nd positive lens unit and the 1st negative lens unit
is smaller at the telephoto end than at the wide angle end. The
distance between the 3rd positive lens unit and the 2nd positive
lens unit varies during zooming from the wide angle end to the
telephoto end.
Inventors: |
Takahashi; Toshio; (Tokyo,
JP) ; Kodama; Hiroshi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OLYMPUS CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
49946250 |
Appl. No.: |
14/840699 |
Filed: |
August 31, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13935908 |
Jul 5, 2013 |
9158098 |
|
|
14840699 |
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Current U.S.
Class: |
348/360 |
Current CPC
Class: |
G02B 15/173 20130101;
G02B 15/14 20130101; H04N 5/23209 20130101; G02B 15/20 20130101;
G02B 15/22 20130101; H04N 5/23296 20130101 |
International
Class: |
G02B 15/14 20060101
G02B015/14; H04N 5/232 20060101 H04N005/232; H04N 5/225 20060101
H04N005/225 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 20, 2012 |
JP |
2012-161533 |
Claims
1. An image pickup apparatus comprising: a zoom lens, and an image
pickup element arranged on the image side of the zoom lens, wherein
the image pickup apparatus has an image pickup surface and converts
an image formed by the zoom lens into an electrical signal, the
zoom lens comprises a first positive lens unit having a positive
refractive power located closest to the object side, a first
negative lens unit having a negative refractive power arranged on
the image side of the first positive lens unit, and an image side
lens unit group arranged on the image side of the first negative
lens unit, the first positive lens unit is located closer to the
object side at the telephoto end than at the wide angle end, the
distance between the first negative lens unit and the first
positive lens unit is larger at the telephoto end than at the wide
angle end, the distance between the image side lens unit group and
the first negative lens unit varies during zooming from the wide
angle end to the telephoto end, the image side lens unit group
comprises a second positive lens unit having a positive refractive
power and a third positive lens unit having a positive refractive
power and arranged closer to the image side than the second
positive lens unit, the distance between the second positive lens
unit and the first negative lens unit is smaller at the telephoto
end than at the wide angle end, the distance between the third
positive lens unit and the second positive lens unit varies during
zooming from the wide angle end to the telephoto end, the first
positive lens unit comprises a plurality of positive lens and at
least one negative lens, an aperture stop is arranged between the
first negative lens unit and the image side lens unit group, at the
telephoto end, the aperture stop is located closer to the object
side than a position of a surface vertex of a lens which is
positioned closer to the object side among lenses in the image side
lens unit group, and the following conditional expressions (2) and
(3) are satisfied: 32.degree.<arc
tan(IH.sub.MAX/f.sub.w)<55.degree. (2), and
0.45<TL.sub.t/f.sub.t<0.70 (3), where f.sub.t is the focal
length of the entire zoom lens system at the telephoto end, f.sub.w
is the focal length of the entire zoom lens system at the wide
angle end, IH.sub.MAX is the largest image height of the image
formed on the image pickup surface or the largest value thereof if
the value of the largest image height varies,
TL.sub.t=TZL.sub.t+FB.sub.t, where TZL.sub.t is the distance on the
optical axis from the object side surface to the image side surface
of the zoom lens at the telephoto end, and FB.sub.t is the back
focus of the zoom lens at the telephoto end expressed in the
equivalent air distance.
2. The image pickup apparatus according to claim 1, wherein the
following conditional expression (3-1) is satisfied:
0.45<TL.sub.t/f.sub.t<0.65 (3-1), where f.sub.t is the focal
length of the entire zoom lens system at the telephoto end,
TL.sub.t=TZL.sub.t+FB.sub.t, where TZL.sub.t is the distance on the
optical axis from the object side surface to the image side surface
of the zoom lens at the telephoto end, and FB.sub.t is the back
focus of the zoom lens at the telephoto end expressed in the
equivalent air distance.
3. The image pickup apparatus according to claim 1, wherein the
following conditional expression (1-1) is satisfied:
20<f.sub.t/f.sub.w (1-1), where f.sub.t is the focal length of
the entire zoom lens system at the telephoto end, f.sub.w is the
focal length of the entire zoom lens system at the wide angle
end.
4. The image pickup apparatus according to claim 2, wherein the
following conditional expression (1-1) is satisfied:
20<f.sub.t/f.sub.w (1-1), where f.sub.t is the focal length of
the entire zoom lens system at the telephoto end, f.sub.w is the
focal length of the entire zoom lens system at the wide angle
end.
5. The image pickup apparatus according to claim 1, wherein the
first positive lens unit comprises two positive lenses and one
negative lens, the total number of lenses included in the first
positive lens unit is three, and a specific positive lens having
the largest thickness on the optical axis among the positive lenses
in the first positive lens unit satisfies the following conditional
expression (5): 0.25d.sub.P1P/D.sub.1P<0.55 (5), where d.sub.P1P
is the thickness of the specific positive lens on the optical axis,
and D.sub.1P is the thickness of the first positive lens unit on
the optical axis.
6. The image pickup apparatus according to claim 2, wherein the
first positive lens unit comprises two positive lenses and one
negative lens, the total number of lenses included in the first
positive lens unit is three, and a specific positive lens having
the largest thickness on the optical axis among the positive lenses
in the first positive lens unit satisfies the following conditional
expression (5): 0.25d.sub.P1P/D.sub.1P<0.55 (5), where d.sub.P1P
is the thickness of the specific positive lens on the optical axis,
and D.sub.1P is the thickness of the first positive lens unit on
the optical axis.
7. The image pickup apparatus according to claim 3, wherein the
first positive lens unit comprises two positive lenses and one
negative lens, the total number of lenses included in the first
positive lens unit is three, and a specific positive lens having
the largest thickness on the optical axis among the positive lenses
in the first positive lens unit satisfies the following conditional
expression (5): 0.25d.sub.P1P/D.sub.1P<0.55 (5), where d.sub.P1P
is the thickness of the specific positive lens on the optical axis,
and D.sub.1P is the thickness of the first positive lens unit on
the optical axis.
8. The image pickup apparatus according to claim 1, wherein the
first positive lens unit includes four lenses.
9. The image pickup apparatus according to claim 1, wherein the
image side lens unit group comprises a second negative lens unit
having a negative refractive power arranged between the second
positive lens unit and the third positive lens unit, and the
distance between the second negative lens unit and the second
positive lens unit and the distance between the second negative
lens unit and the third positive lens unit vary during zooming from
the wide angle end to the telephoto end.
10. The image pickup apparatus according to claim 2, wherein the
image side lens unit group comprises a second negative lens unit
having a negative refractive power arranged between the second
positive lens unit and the third positive lens unit, and the
distance between the second negative lens unit and the second
positive lens unit and the distance between the second negative
lens unit and the third positive lens unit vary during zooming from
the wide angle end to the telephoto end.
11. The image pickup apparatus according to claim 3, wherein the
image side lens unit group comprises a second negative lens unit
having a negative refractive power arranged between the second
positive lens unit and the third positive lens unit, and the
distance between the second negative lens unit and the second
positive lens unit and the distance between the second negative
lens unit and the third positive lens unit vary during zooming from
the wide angle end to the telephoto end.
12. The image pickup apparatus according to claim 6, wherein the
image side lens unit group comprises a second negative lens unit
having a negative refractive power arranged between the second
positive lens unit and the third positive lens unit, and the
distance between the second negative lens unit and the second
positive lens unit and the distance between the second negative
lens unit and the third positive lens unit vary during zooming from
the wide angle end to the telephoto end.
13. The image pickup apparatus according to claim 1, wherein the
third positive lens unit consists of one lens component, where the
lens component is a lens block having only two surfaces, namely, an
object-side surface and an image-side surface, are in contact with
air.
14. The image pickup apparatus according to claim 2, wherein the
third positive lens unit consists of one lens component, where the
lens component is a lens block having only two surfaces, namely, an
object-side surface and an image-side surface, are in contact with
air.
15. The image pickup apparatus according to claim 3, wherein the
third positive lens unit consists of one lens component, where the
lens component is a lens block having only two surfaces, namely, an
object-side surface and an image-side surface, are in contact with
air.
16. The image pickup apparatus according to claim 12, wherein the
third positive lens unit consists of one lens component, where the
lens component is a lens block having only two surfaces, namely, an
object-side surface and an image-side surface, are in contact with
air.
17. The image pickup apparatus according to claim 1, wherein the
following conditional expression (14) is satisfied:
0.4<(TL.sub.t-TL.sub.w)/TL.sub.w (14), where
TL.sub.t=TZL.sub.t+FB.sub.t, and TL.sub.w=TZL.sub.w+FB.sub.w, where
TZL.sub.t is the distance on the optical axis from the object side
surface to the image side surface of the zoom lens at the telephoto
end, FB.sub.t is the back focus of the zoom lens at the telephoto
end expressed in the equivalent air distance, TZL.sub.w is the
distance on the optical axis from the object side surface to the
image side surface of the zoom lens at the wide angle end, and
FB.sub.w is the back focus of the zoom lens at the wide angle end
expressed in the equivalent air distance.
18. The image pickup apparatus according to claim 2, wherein the
following conditional expression (14) is satisfied:
0.4<(TL.sub.t-TL.sub.w)/TL.sub.w (14), where
TL.sub.t=TZL.sub.t+FB.sub.t, and TL.sub.w=TZL.sub.w+FB.sub.w, where
TZL.sub.t is the distance on the optical axis from the object side
surface to the image side surface of the zoom lens at the telephoto
end, FB.sub.t is the back focus of the zoom lens at the telephoto
end expressed in the equivalent air distance, TZL.sub.w is the
distance on the optical axis from the object side surface to the
image side surface of the zoom lens at the wide angle end, and
FB.sub.w is the back focus of the zoom lens at the wide angle end
expressed in the equivalent air distance.
19. The image pickup apparatus according to claim 3, wherein the
following conditional expression (14) is satisfied:
0.4<(TL.sub.t-TL.sub.w)/TL.sub.w (14), where
TL.sub.t=TZL.sub.t+FB.sub.t, and TL.sub.w=TZL.sub.w+FB.sub.w, where
TZL.sub.t is the distance on the optical axis from the object side
surface to the image side surface of the zoom lens at the telephoto
end, FB.sub.t is the back focus of the zoom lens at the telephoto
end expressed in the equivalent air distance, TZL.sub.w is the
distance on the optical axis from the object side surface to the
image side surface of the zoom lens at the wide angle end, and
FB.sub.w is the back focus of the zoom lens at the wide angle end
expressed in the equivalent air distance.
20. The image pickup apparatus according to claim 16, wherein the
following conditional expression (14) is satisfied:
0.4<(TL.sub.t-TL.sub.w)/TL.sub.w (14), where
TL.sub.t=TZL.sub.t+FB.sub.t, and TL.sub.w=TZL.sub.w+FB.sub.w, where
TZL.sub.t is the distance on the optical axis from the object side
surface to the image side surface of the zoom lens at the telephoto
end, FB.sub.t is the back focus of the zoom lens at the telephoto
end expressed in the equivalent air distance, TZL.sub.w is the
distance on the optical axis from the object side surface to the
image side surface of the zoom lens at the wide angle end, and
FB.sub.w is the back focus of the zoom lens at the wide angle end
expressed in the equivalent air distance.
21. The image pickup apparatus according to claim 1, wherein the
first negative lens unit comprises in order from an object side, a
negative lens, a negative lens, and a positive lens.
22. The image pickup apparatus according to claim 2, wherein the
first negative lens unit comprises in order from an object side, a
negative lens, a negative lens, and a positive lens.
23. The image pickup apparatus according to claim 3, wherein the
first negative lens unit comprises in order from an object side, a
negative lens, a negative lens, and a positive lens.
24. The image pickup apparatus according to claim 20, wherein the
first negative lens unit comprises in order from an object side, a
negative lens, a negative lens, and a positive lens.
25. The image pickup apparatus according to claim 1, wherein the
following conditional expressions (7) and (8) are satisfied:
0.1<f.sub.1P/f.sub.t<0.5 (7), and
-0.15<f.sub.1N/f.sub.t<-0.02 (8), where f.sub.1P is the focal
length of the first positive lens unit, f.sub.1N is the focal
length of the first negative lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
26. The image pickup apparatus according to claim 2, wherein the
following conditional expressions (7) and (8) are satisfied:
0.1<f.sub.1P/f.sub.t<0.5 (7), and
-0.15<f.sub.1N/f.sub.t<-0.02 (8), where f.sub.1P is the focal
length of the first positive lens unit, f.sub.1N is the focal
length of the first negative lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
27. The image pickup apparatus according to claim 3, wherein the
following conditional expressions (7) and (8) are satisfied:
0.1<f.sub.1P/f.sub.t<0.5 (7), and
-0.15<f.sub.1N/f.sub.t<-0.02 (8), where f.sub.1P is the focal
length of the first positive lens unit, f.sub.1N is the focal
length of the first negative lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
28. The image pickup apparatus according to claim 24, wherein the
following conditional expressions (7) and (8) are satisfied:
0.1<f.sub.1P/f.sub.t<0.5 (7), and
-0.15<f.sub.1N/f.sub.t<-0.02 (8), where f.sub.1P is the focal
length of the first positive lens unit, f.sub.1N is the focal
length of the first negative lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
29. The image pickup apparatus according to claim 1, wherein the
following conditional expressions (9) and (11) are satisfied:
0.05<f.sub.2P/f.sub.t<0.15 (9), and
0.05f.sub.3P/f.sub.t<0.20 (11), where f.sub.2P is the focal
length of the second positive lens unit, f.sub.3P is the focal
length of the third positive lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
30. The image pickup apparatus according to claim 2, wherein the
following conditional expressions (9) and (11) are satisfied:
0.05<f.sub.2P/f.sub.t<0.15 (9), and
0.05f.sub.3P/f.sub.t<0.20 (11), where f.sub.2P is the focal
length of the second positive lens unit, f.sub.3P is the focal
length of the third positive lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
31. The image pickup apparatus according to claim 3, wherein the
following conditional expressions (9) and (11) are satisfied:
0.05<f.sub.2P/f.sub.t<0.15 (9), and
0.05f.sub.3P/f.sub.t<0.20 (11), where f.sub.2P is the focal
length of the second positive lens unit, f.sub.3P is the focal
length of the third positive lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
32. The image pickup apparatus according to claim 28, wherein the
following conditional expressions (9) and (11) are satisfied:
0.05<f.sub.2P/f.sub.t<0.15 (9), and
0.05f.sub.3P/f.sub.t<0.20 (11), where f.sub.2P is the focal
length of the second positive lens unit, f.sub.3P is the focal
length of the third positive lens unit, and f.sub.t is the focal
length of the entire zoom lens system at the telephoto end.
33. The image pickup apparatus according to claim 9, wherein the
following conditional expression (10) is satisfied:
-0.25<f.sub.2N/f.sub.t<-0.05 (10), where f.sub.2N is the
focal length of the second negative lens unit, and f.sub.t is the
focal length of the entire zoom lens system at the telephoto
end.
34. The image pickup apparatus according to claim 10, wherein the
following conditional expression (10) is satisfied:
-0.25<f.sub.2N/f.sub.t<-0.05 (10), where f.sub.2N is the
focal length of the second negative lens unit, and f.sub.t is the
focal length of the entire zoom lens system at the telephoto
end.
35. The image pickup apparatus according to claim 11, wherein the
following conditional expression (10) is satisfied:
-0.25<f.sub.2N/f.sub.t<-0.05 (10), where f.sub.2N is the
focal length of the second negative lens unit, and f.sub.t is the
focal length of the entire zoom lens system at the telephoto
end.
36. The image pickup apparatus according to claim 12, wherein the
following conditional expression (10) is satisfied:
-0.25<f.sub.2N/f.sub.t<-0.05 (10), where f.sub.2N is the
focal length of the second negative lens unit, and f.sub.t is the
focal length of the entire zoom lens system at the telephoto
end.
37.-59. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a division of U.S. patent
application Ser. No. 13/935,908 filed on Jul. 5, 2013, which is
based upon and claims the benefit of priority from the prior
Japanese Patent Application No. 2012-161533 filed on Jul. 20, 2012;
the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an image pickup apparatus
and a zoom lens used in the image pickup apparatus.
[0004] 2. Description of the Related Art
[0005] There has been known a zoom lens including a first positive
lens unit having a positive refractive power located closest to the
object side, a first negative lens unit having a negative
refractive power arranged on the image side of the first positive
lens unit, and an image side lens unit arranged on the image side
of the first negative lens unit. An image pickup apparatus equipped
with such a zoom lens has also been known. There are various types
of zoom lenses used in image pickup apparatuses. Such zoom lenses
having a high zoom ratio are disclosed in Japanese Patent
Application Laid-Open Nos. 2011-90265, 2012-27308, 2009-251280, and
2011-48320.
SUMMARY OF THE INVENTION
[0006] An image pickup apparatus according to the present invention
comprises:
[0007] a zoom lens, and
[0008] an image pickup element arranged on the image side of the
zoom lens, wherein
[0009] the image pickup apparatus has an image pickup surface and
converts an image formed by the zoom lens into an electrical
signal,
[0010] the zoom lens comprises a first positive lens unit having a
positive refractive power located closest to the object side, a
first negative lens unit having a negative refractive power
arranged on the image side of the first positive lens unit, and an
image side lens unit group arranged on the image side of the first
negative lens unit,
[0011] the first positive lens unit is located closer to the object
side at the telephoto end than at the wide angle end,
[0012] the distance between the first negative lens unit and the
first positive lens unit is larger at the telephoto end than at the
wide angle end,
[0013] the distance between the image side lens unit group and the
first negative lens unit varies during zooming from the wide angle
end to the telephoto end,
[0014] the image side lens unit group comprises a second positive
lens unit having a positive refractive power and a third positive
lens unit having a positive refractive power and arranged closer to
the image side than the second positive lens unit,
[0015] the distance between the second positive lens unit and the
first negative lens unit is smaller at the telephoto end than at
the wide angle end,
[0016] the distance between the third positive lens unit and the
second positive lens unit varies during zooming from the wide angle
end to the telephoto end,
[0017] the first positive lens unit comprises a plurality of
positive lens and at least one negative lens, and
[0018] the following conditional expressions (1), (2), and (3) are
satisfied:
20<f.sub.t/f.sub.w<60 (1),
32.degree.<arc tan(IH.sub.MAX/f.sub.w)<55.degree. (2),
and
0.45<TL.sub.t/f.sub.t<0.70 (3),
where f.sub.t is the focal length of the entire zoom lens system at
the telephoto end, f.sub.w is the focal length of the entire zoom
lens system at the wide angle end, IH.sub.MAX is the largest image
height of the image formed on the image pickup surface or the
largest value thereof if the value of the largest image height
varies, TL.sub.t=TZL.sub.t+FB.sub.t, where TZL.sub.t is the
distance on the optical axis from the object side surface to the
image side surface of the zoom lens at the telephoto end, and
FB.sub.t is the back focus of the zoom lens at the telephoto end
expressed in the equivalent air distance.
[0019] A zoom lens according to the present invention
comprises:
[0020] a first positive lens unit having a positive refractive
power located closest to the object side;
[0021] a first negative lens unit having a negative refractive
power arranged on the image side of the first positive lens unit;
and
[0022] an image side lens unit group arranged on the image side of
the first negative lens unit, wherein
[0023] the first positive lens unit is located closer to the object
side at the telephoto end than at the wide angle end,
[0024] the distance between the first negative lens unit and the
first positive lens unit is larger at the telephoto end than at the
wide angle end,
[0025] the distance between the image side lens unit group and the
first negative lens unit varies during zooming from the wide angle
end to the telephoto end,
[0026] the image side lens unit group comprises a second positive
lens unit having a positive refractive power and a third positive
lens unit having a positive refractive power and arranged closer to
the image side than the second positive lens unit,
[0027] the distance between the second positive lens unit and the
first negative lens unit is smaller at the telephoto end than at
the wide angle end,
[0028] the distance between the third positive lens unit and the
second positive lens unit varies during zooming from the wide angle
end to the telephoto end,
[0029] the following conditional expressions (1), (3), and (A) are
satisfied, and
[0030] the first positive lens unit comprises a plurality of
positive lenses, at least one of which satisfies the following
conditional expression (4), and at least one negative lens:
20<f.sub.t/f.sub.w<60 (1),
0.45<TL.sub.t/f.sub.t<0.70 (3),
90<.nu.d (4), and
S.sub.1P.gtoreq.S.sub.1N.gtoreq.S.sub.2P>S.sub.3P (A),
where f.sub.t is the focal length of the entire zoom lens system at
the telephoto end, f.sub.w is the focal length of the entire zoom
lens system at the wide angle end, TL.sub.t=TZL.sub.t+FB.sub.t,
TZL.sub.t is the distance on the optical axis from the object side
surface to the image side surface of the zoom lens at the telephoto
end, FB.sub.t is the back focus of the zoom lens at the telephoto
end expressed in the equivalent air distance, .nu.d is the Abbe
constant with respect to the d-line of the positive lens in the
first positive lens unit, S.sub.1P is the total number of lenses
included in the first positive lens unit, S.sub.1N is the total
number of lenses included in the first negative lens unit, S.sub.2p
is the total number of lenses included in the second positive lens
unit, and S.sub.3P is the total number of lenses included in the
third positive lens unit.
[0031] An image pickup apparatus according to the present invention
comprises:
[0032] the above-described zoom lens; and
[0033] an image pickup element arranged on the image side of the
zoom lens,
wherein the image pickup has an image pickup surface and converts
an image formed by the zoom lens into an electrical signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIGS. 1A and 1B are cross sectional view of a zoom lens
according to a first example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0035] FIGS. 2A and 2B are cross sectional view of a zoom lens
according to a second example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0036] FIGS. 3A and 3B are cross sectional view of a zoom lens
according to a third example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0037] FIGS. 4A and 4B are cross sectional view of a zoom lens
according to a fourth example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0038] FIGS. 5A and 5B are cross sectional view of a zoom lens
according to a fifth example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0039] FIGS. 6A and 6B are cross sectional view of a zoom lens
according to a sixth example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0040] FIGS. 7A and 7B are cross sectional view of a zoom lens
according to a seventh example of the present invention in the
state in which the zoom lens is focused on an object point at
infinity respectively at the wide angle end and the telephoto
end;
[0041] FIGS. 8A and 8B are cross sectional view of a zoom lens
according to a eighth example of the present invention in the state
in which the zoom lens is focused on an object point at infinity
respectively at the wide angle end and the telephoto end;
[0042] FIGS. 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H, 91, 9J, 9K, and 9L are
aberration diagrams of the zoom lens according to the first example
in the state in which the zoom lens is focused at an object point
at infinity;
[0043] FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K,
and 10L are aberration diagrams of the zoom lens according to the
second example in the state in which the zoom lens is focused at an
object point at infinity;
[0044] FIGS. 11A, 11B, 11C, 11D, 11E, 11F, 11G, 11H, 11I, 11J, 11K,
and 11L are aberration diagrams of the zoom lens according to the
third example in the state in which the zoom lens is focused at an
object point at infinity;
[0045] FIGS. 12A, 12B, 12C, 12D, 12E, 12F, 12G, 12H, 12I, 12J, 12K,
and 12L are aberration diagrams of the zoom lens according to the
fourth example in the state in which the zoom lens is focused at an
object point at infinity;
[0046] FIGS. 13A, 13B, 13C, 13D, 13E, 13F, 13G, 13H, 13I, 13J, 13K,
and 13L are aberration diagrams of the zoom lens according to the
fifth example in the state in which the zoom lens is focused at an
object point at infinity;
[0047] FIGS. 14A, 14B, 14C, 14D, 14E, 14F, 14G, 14H, 14I, 14J, 14K,
and 14L are aberration diagrams of the zoom lens according to the
sixth example in the state in which the zoom lens is focused at an
object point at infinity;
[0048] FIGS. 15A, 15B, 15C, 15D, 15E, 15F, 15G, 15H, 15I, 15J, 15K,
and 15L are aberration diagrams of the zoom lens according to the
seventh example in the state in which the zoom lens is focused at
an object point at infinity;
[0049] FIGS. 16A, 16B, 16C, 16D, 16E, 16F, 16G, 16H, 16I, 16J, 16K,
and 16L are aberration diagrams of the zoom lens according to the
eighth example in the state in which the zoom lens is focused at an
object point at infinity;
[0050] FIG. 17 is a cross sectional view of a digital camera
equipped with a zoom lens according to the present invention;
[0051] FIG. 18 is a front perspective view showing the outer
appearance of the digital camera;
[0052] FIG. 19 is a rear perspective view showing the outer
appearance of the digital camera; and
[0053] FIG. 20 is a block diagram showing the relevant interval
circuit configuration of the digital camera.
DETAILED DESCRIPTION OF THE INVENTION
[0054] In the following, some embodiments and examples of the image
pickup apparatus and the zoom lens used in the image pickup
apparatus according to the present invention will be described with
reference to the drawings. It should be understood, however, that
the present invention is by no means limited by the embodiments or
examples.
[0055] An image pickup apparatus according to an embodiment of the
invention includes a zoom lens and an image pickup element arranged
on the image side of the zoom lens. The image pickup element has an
image pickup surface and converts an image formed by the zoom lens
into an electrical signal. The zoom lens includes a first positive
lens unit having a positive refractive power located closest to the
object side among the lens units in the zoom lens, a first negative
lens unit having a negative refractive power arranged on the image
side of the first positive lens unit, and an image side lens unit
group arranged on the image side of the first negative lens
unit.
[0056] In this zoom lens, the first positive lens unit is located
closer to the object side at the telephoto end than at the wide
angle end, the distance between the first negative lens unit and
the first positive lens unit is larger at the telephoto end than at
the wide angle end, and the distance between the image side lens
unit group and the first negative lens unit varies during zooming
from the wide angle end to the telephoto end.
[0057] As described above, the first positive lens unit moves
during zooming in such a way that it is located closer to the
object side at the telephoto end than at the wide angle end. This
can lead to a reduction in the overall length of the zoom lens.
This consequently allows the optical system to have a wide angle of
view while keeping the effective diameter of the first positive
lens unit small. The above-described movement of the first positive
lens unit helps to reduce the diameter of the first positive lens
unit and the widening of the angle of view.
[0058] Moreover, varying the distances between the lens units in
the above-described manner enables the first negative lens unit and
the second positive lens unit to contribute to the variation of the
magnification. Therefore, the above-described variations in the
distances helps to achieve an adequate zoom ratio.
[0059] In this zoom lens, moreover, the image side lens unit group
includes a second positive lens unit having a positive refractive
power, a third positive lens unit having a positive refractive
power and arranged closer to the image side than the second
positive lens unit, the distance between the second positive lens
unit and the first negative lens unit is smaller at the telephoto
end than at the wide angle end, and the distance between the third
positive lens unit and the second positive lens unit varies during
zooming from the wide angle end to the telephoto end.
[0060] Including the third positive lens unit in the image side
lens unit group helps to shift the position of the exit pupil away
from the image plane (or the image pickup surface).
[0061] In this zoom lens, moreover, the first positive lens unit
includes a plurality of positive lenses and at least one negative
lens. As the first positive lens unit includes a plurality of
positive lenses, the first positive lens unit can have an
appropriate positive refractive power. As the first positive lens
unit includes a negative lens, chromatic aberration can be
corrected excellently in the first positive lens unit.
[0062] In the image pickup apparatus according to this embodiment,
the following conditional expressions (1), (2), and (3) are
satisfied:
20<f.sub.t/f.sub.w<60 (1),
32.degree.<arc tan(IH.sub.MAX/f.sub.w)<55.degree. (2),
and
0.46<TL.sub.t/f.sub.t<0.70 (3),
where f.sub.t is the focal length of the entire zoom lens system at
the telephoto end, f.sub.w is the focal length of the entire zoom
lens system at the wide angle end, IH.sub.MAX is the largest image
height of the image formed on the image pickup surface or the
largest value thereof if the value of the largest image height
varies, TL.sub.t=TZL.sub.t+FB.sub.t, where TZL.sub.t is the
distance on the optical axis from the object side surface to the
image side surface of the zoom lens at the telephoto end, and
FB.sub.t is the back focus of the zoom lens at the telephoto end
expressed in the equivalent air distance.
[0063] Conditional expression (1) specifies a preferred range of
the zoom ratio of the zoom lens. If the term in conditional
expression (1) has a value not smaller than the lower limit, angles
of view suitable for various shooting situations will be available.
On the other hand, if the term in conditional expression (1) has a
value not larger than the upper limit, the zoom lens can have
sufficient brightness, or speed at the telephoto end.
[0064] Conditional expression (2) specifies a preferred range of
the focal length at the wide angle end of the zoom lens. If the
term in conditional expression (2) has a value not smaller than the
lower limit, angles of view suitable for various shooting
situations will be available. On the other hand, if the term in
conditional expression (2) has a value not larger than the upper
limit, reduction of the diameter of the first positive lens unit
and reduction of off-axis aberrations in the focal length range
near the wide angle end will be facilitated.
[0065] In some zoom lenses, the height of the image formed on the
image pickup surface is varied with zooming. For example, the image
height at the wide angle end is intentionally made smaller than the
image height at the telephoto end or at an intermediate focal
length state, and images picked up at the wide angle end is
processed by image processing to have an image height equal to the
image height at the telephoto end or at the intermediate focal
length state. In the case of zoom lenses in which the image height
varies with zooming, the value of IH.sub.MAX is the largest value
of the varying image height.
[0066] Conditional expression (3) specifies a preferred range of
the telephoto ratio of the zoom lens at the telephoto end. If the
term in conditional expression (3) has a value not smaller than the
lower limit, reduction of axial chromatic aberration in the focal
length range near the telephoto end will be facilitated. On the
other hand, if the term in conditional expression (3) has a value
not larger than the upper limit, the amount of movement of the
first lens unit can be reduced. Consequently, the size of the zoom
lens can be made small throughout the entire zoom range (from the
wide angle end to the telephoto end). Therefore, not exceeding the
upper limit of conditional expression (3) helps to reduce the size
of the image pickup apparatus including the lens barrel.
[0067] In the image pickup apparatus according to this embodiment,
it is preferred that the total number of lenses located closer the
to the image side than the first negative lens unit be equal to or
less than 7.
[0068] Reduction in the total number of lenses helps to reduce the
overall length of the zoom lens and reduction in the cost.
[0069] It is preferred that the total number of lenses located
closer to the image side than the first negative lens unit be equal
to or less than 6. It is more preferred that the total number of
lenses located closer to the image side than the first negative
lens unit be equal to or less than 5.
[0070] In the image pickup apparatus according to this embodiment,
it is preferred that the first positive lens unit include at least
one positive lens that satisfies the following conditional
expression (4):
90<.nu.d (4),
where .nu.d is the Abbe constant with respect to the d-line of the
positive lens in the first positive lens unit.
[0071] The high refractive power of the first positive lens unit
helps to maintain the low telephoto ratio and achieving a
sufficiently high zoom ratio. However, the high refractive power of
the first positive lens unit tends to lead to generation of
chromatic aberration in the first positive lens unit. Therefore, in
order to reduce chromatic aberration involved by the high
refractive power, it is preferred that a positive lens that
satisfies conditional expression (4), i.e. a positive lens with low
dispersion, be used in the first positive lens unit.
[0072] Including at least one positive lens that satisfies
conditional expression (4) in the first positive lens unit helps to
reduce chromatic aberration generated in the first positive lens
unit. Inconsequence, the optical performance (or imaging
performance) of the zoom lens can be improved, leading to an
improvement in the image quality in the image pickup apparatus. For
the above reason, using the positive lens that satisfies
conditional expression (4) helps to improve the image quality in
the image pickup apparatus that satisfies the above-mentioned
conditional expressions (1) to (3).
[0073] In the image pickup apparatus according to this embodiment,
it is preferred that a specific positive lens having the largest
thickness on the optical axis among the positive lenses in the
first positive lens unit satisfy conditional expression (4).
[0074] The first positive lens unit includes a plurality of
positive lenses. If the specific lens among them or the positive
lens having the largest thickness on the optical axis is a lens
that satisfies conditional expression (4), it is easy to design
this lens to have a high positive refractive power. Consequently,
the optical performance of the zoom lens can be improved, enabling
improvement in the image quality in the image pickup apparatus.
Therefore, the specific positive lens satisfying conditional
expression (4) helps to improve both the optical performance and
the image quality.
[0075] In the image pickup apparatus according to this embodiment,
it is preferred that the first positive lens unit be composed of
two positive lenses and one negative lens and that a specific
positive lens having the largest thickness on the optical axis
among the positive lenses in the first positive lens unit satisfy
the following conditional expression (5):
0.25d.sub.P1P/D.sub.1P<0.55 (5),
where d.sub.P1P is the thickness of the specific positive lens on
the optical axis, and D.sub.1P is the thickness of the first
positive lens unit on the optical axis.
[0076] As the first positive lens unit is composed of three lenses,
the first positive lens unit can be made slim. When the first
positive lens unit is composed of three lenses, it is preferred
that a specific lens or the positive lens that has the largest
thickness on the optical axis satisfy conditional expression (5).
This allows the first positive lens unit to have an sufficiently
high positive refractive power. The number of positive lenses
satisfying conditional expression (5) may be either one or two.
[0077] Not falling short of the lower limit of conditional
expression (5) helps to design the first positive lens unit to have
a sufficiently high refractive power. On the other hand, if the
term in conditional expression (5) has a value not larger than the
upper limit, both of the two positive lenses can contribute to the
positive refractive power. Therefore, not exceeding the upper limit
of conditional expression (5) helps to correct aberrations in the
first positive lens unit.
[0078] In the image pickup apparatus according to this embodiment,
it is preferred that the first positive lens unit include four
lenses.
[0079] Including a relatively large number of lenses in the first
positive lens unit helps to design the first positive lens unit to
have a sufficiently high refractive power and to reduce
aberrations. This configuration may be adopted in the zoom lens
according to another embodiment that will be described later.
[0080] Moreover, in the image pickup apparatus according to this
embodiment, it is preferred that at least two positive lenses among
the four lenses satisfy the following conditional expression
(4):
90<.nu.d (4),
where .nu.d is the Abbe constant with respect to the d-line of the
positive lenses in the first positive lens unit.
[0081] If at least two lenses among the four lenses satisfy
conditional expression (4), chromatic aberration generated in the
first positive lens unit can be reduced, and the first positive
lens unit can be designed to have a sufficiently high positive
refractive power. Therefore, including at least two lenses that
satisfy conditional expression (4) further helps to design the
first positive lens unit to have a sufficiently high refractive
power and to reduce aberrations. In the zoom lens according to the
later described embodiment also, it is preferred that conditional
expression (4) be satisfied.
[0082] In the image pickup apparatus according to this embodiment,
it is preferred that the image side lens unit group include a
second negative lens unit having a negative refractive power
arranged between the second positive lens unit and the third
positive lens unit and that the distance between the second
negative lens unit and the second positive lens unit and the
distance between the second negative lens unit and the third
positive lens unit vary during zooming from the wide angle end to
the telephoto end.
[0083] In the above configuration, off-axis beams emergent from the
second positive lens unit are refracted by the second negative lens
unit in directions away from the optical axis. Thereafter, the
off-axis beams emergent from the second negative lens unit are
refracted by the third positive lens unit (in directions
approaching the optical axis) to travel toward the image pickup
surface. Therefore, this configuration helps to reduce the size of
portion of the optical system on the object side of the second
negative lens unit. Moreover, the second negative lens unit can be
designed to function as a compensator, leading to improvement in
the design flexibility. It is preferred that this configuration be
adopted in the zoom lens according to the later-described
embodiment.
[0084] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expressions (A) and
(B) be satisfied:
S.sub.1P.gtoreq.S.sub.1N.gtoreq.S.sub.2P>S.sub.3P (A), and
S.sub.1P.gtoreq.S.sub.1N.gtoreq.S.sub.2P>S.sub.2N (B),
where S.sub.1P is the total number of lenses included in the first
positive lens unit, S.sub.1N is the total number of lenses included
in the first negative lens unit, S.sub.2P is the total number of
lenses included in the second positive lens unit, S.sub.2N is the
total number of lenses included in the second negative lens unit,
and S.sub.3P is the total number of lenses included in the third
positive lens unit.
[0085] The zoom lens includes lens units that greatly contribute to
size reduction of the optical system and to high zoom ratio and
lens units that do not (lens units that do not greatly contribute
to size reduction of the optical system and to high zoom ratio). It
is preferred that the lens units that greatly contribute to size
reduction of the optical system and to high zoom ratio be designed
to include a larger number of lenses in total in order to have a
sufficiently high refractive power and to enable reduction of
aberrations and that the lens units that do not be designed to
include a smaller number of lenses to thereby reduce the cost of
the optical system.
[0086] If one of conditional expressions (A) and (B) is satisfied,
the lens units including larger numbers of lenses are arranged
closer to the object side, and the lens unit including smaller
numbers of lenses are arranged closer to the image side.
Consequently, each lens unit can be designed to have an appropriate
refractive power, and reduction of aberrations and cost reduction
can be achieved. If conditional expressions (A) and (B) are both
satisfied, the above advantages can be achieved more effectively.
In the zoom lens according to the later described embodiment also,
it is preferred that the conditional expression (B) be
satisfied.
[0087] In the image pickup apparatus according to this embodiment,
it is preferred that the second negative lens unit include a
negative lens that satisfies the following conditional expression
(6) and that the second negative lens unit move toward the image
side during focusing from infinity to a short distance:
70<.nu.d.sub.N2N (6),
where .nu.d.sub.N2N is the Abbe constant of the negative lens in
the second negative lens unit with respect to the d-line.
[0088] If conditional expression (6) is satisfied, chromatic
aberration generated in the second negative lens unit can be made
small. In addition, satisfying conditional expression (6) helps to
reduce the number of lenses included in the second negative lens
unit and to reduce the weight of the second negative lens unit.
[0089] If conditional expression (6) is satisfied, the second
negative lens unit can be made small and light in weight, allowing
the second negative lens unit to serve as a focusing lens unit.
This helps to reduce the load on driving unit for focusing. As a
lens unit is moved, the size of the image (on the image pickup
surface) generally changes with the movement of the lens unit. In
the case where the second negative unit is moved, such change in
the size can be made small. For this reason, the second negative
lens unit is preferably used as the focusing lens unit in video
shooting.
[0090] In the image pickup apparatus according to this embodiment,
it is preferred that following conditional expressions (7) and (8)
be satisfied:
0.1<f.sub.1P/f.sub.t<0.5 (7), and
-0.15<f.sub.1N/f.sub.t<-0.02 (8),
where f.sub.1P is the focal length of the first positive lens unit,
f.sub.1N is the focal length of the first negative lens unit, and
f.sub.t is the focal length of the entire zoom lens system at the
telephoto end.
[0091] Conditional expressions (7) and (8) specify preferred ranges
of the focal lengths of the first positive lens unit and the first
negative lens unit respectively. It is preferred that one or both
of conditional expressions (7) and (8) be satisfied. In the zoom
lens according to the later-described embodiment also, it is
preferred that conditional expressions (7) and (8) be
satisfied.
[0092] Not falling short of the lower limit of conditional
expression (7) helps to reduce chromatic aberration in the entire
zoom lens (i.e. to control the generation of chromatic aberration).
On the other hand, not exceeding the upper limit of conditional
expression (7) helps to reduce the overall length of the zoom lens
in the focal length range near the telephoto end and to achieve an
appropriate zoom ratio.
[0093] Not falling short of the lower limit of conditional
expression (8) helps to achieve a sufficiently large angle of view
at the wide angle end and to achieve an appropriate zoom ratio.
Moreover, not falling short of the lower limit of conditional
expression (8) also helps to reduce (or to control the generation
of) curvature of field and chromatic aberration in the entire zoom
lens. On the other hand, not exceeding the upper limit of
conditional expression (8) helps to control variation of
aberrations, in particular variation of curvature of field, with
zooming.
[0094] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expressions (9) and
(11) be satisfied:
0.05<f.sub.2P/f.sub.t<0.15 (9), and
0.05f.sub.3P/f.sub.t<0.20 (11),
where f.sub.2P is the focal length of the second positive lens
unit, f.sub.3P is the focal length of the third positive lens unit,
and f.sub.t is the focal length of the entire zoom lens system at
the telephoto end.
[0095] Conditional expressions (9) and (11) specify preferred
ranges of the focal lengths of the second positive lens unit and
the third positive lens unit respectively. It is preferred that one
or both of conditional expressions (9) and (11) be satisfied.
[0096] Not falling short of the lower limit of conditional
expression (9) helps to reduce (or to control the generation of)
spherical aberration in the focal length range near the telephoto
end. On the other hand, not exceeding the upper limit of
conditional expression (9) helps to achieve appropriate
magnification variation by the second positive lens unit.
[0097] Not falling short of the lower limit of conditional
expression (11) helps to reduce the tilt of the image plane toward
the object side. On the other hand, not exceeding the upper limit
of conditional expression (11) helps to shift the position of the
exit pupil away from the image plane. In cases where the third
positive lens unit is moved to vary the magnification, not
exceeding the upper limit of conditional expression (11) helps to
achieve appropriate magnification variation by the third positive
lens unit.
[0098] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expressions (7),
(8), (9), (10), and (11) be satisfied:
0.1<f.sub.1P/f.sub.t<0.5 (7),
-0.15<f.sub.1N/f.sub.t<-0.02 (8),
0.05<f.sub.2P/f.sub.t<0.15 (9),
-0.25<f.sub.2N/f.sub.t<-0.05 (10), and
0.05f.sub.3P/f.sub.t<0.20 (11),
where f.sub.1P is the focal length of the first positive lens unit,
f.sub.1N is the focal length of the first negative lens unit,
f.sub.2P is the focal length of the second positive lens unit,
f.sub.2N is the focal length of the second negative lens unit,
f.sub.3P is the focal length of the third positive lens unit, and
f.sub.t is the focal length of the entire zoom lens system at the
telephoto end.
[0099] Conditional expressions (7), (8), (9), (10), and (11)
specify preferred ranges of the focal lengths of the first positive
lens unit, the first negative lens unit, the second positive lens
unit, the second negative lens unit, and the third positive lens
unit respectively.
[0100] Technical meaning of conditional expressions (7), (8), (9),
and (11) have been described above.
[0101] Not falling short of the lower limit of conditional
expression (10) helps to reduce the diameter of the zoom lens. On
the other hand, not exceeding the upper limit of conditional
expression (10) helps to reduce (or control the generation of)
coma, curvature of field, and spherical aberration in the second
negative lens unit. In addition, not exceeding the upper limit of
conditional expression (10) helps to reduce variation in
aberrations, in cases where the second negative lens unit is used
as a focusing lens unit.
[0102] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expression (12) be
satisfied:
0.12<D.sub.1P/TL.sub.w (12),
where D.sub.1P is the thickness of the first positive lens unit on
the optical axis, and TL.sub.w=TZL.sub.w+FB.sub.w, where TZL.sub.w
is the distance on the optical axis from the object side surface to
the image side surface of the zoom lens at the wide angle end, and
FB.sub.w is the back focus of the zoom lens at the wide angle end
expressed in the equivalent air distance.
[0103] It is preferred that the thickness of the first positive
lens unit on the optical axis be so large that the term in
conditional expression (12) has a value not smaller than the lower
limit. This helps to increase the flexibility of the lens
configuration. Not falling short of the lower limit of conditional
expression (12) helps to design the first positive lens unit to
have a sufficiently high refractive power while reducing
aberrations. In the zoom lens according to the later-described
embodiment also, it is preferred that conditional expression (12)
be satisfied.
[0104] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expression (13) be
satisfied:
1.2<D.sub.1P/D.sub.1N (13),
where D.sub.1P is the thickness of the first positive lens unit on
the optical axis, and D.sub.1N is the thickness of the first
negative lens unit on the optical axis.
[0105] It is preferred that the thickness of the first positive
lens unit on the optical axis be so large that the term in
conditional expression (13) has a value not smaller than the lower
limit. This helps to increase the flexibility of the lens
configuration. Not falling short of the lower limit of conditional
expression (13) helps to design the first positive lens unit to
have a sufficiently high refractive power while reducing
aberrations.
[0106] It is preferred that the thickness of the first negative
lens unit on the optical axis be so small that the term in
conditional expression (13) has a value not smaller than the lower
limit. This helps to provide an appropriate variable air distances
in front and rear of the first negative lens unit. Not falling
short of the lower limit of conditional expression (13) helps to
achieve an appropriate zoom ratio and to reduce the size of the
zoom lens and the image pickup apparatus. In the zoom lens
according to the later-described embodiment also, it is preferred
that conditional expression (13) be satisfied.
[0107] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expression (14) be
satisfied:
0.4<(TL.sub.t-TL.sub.w)/TL.sub.w (14),
where TL.sub.t=TZL.sub.t+FB.sub.t, and TL.sub.w=TZL.sub.w+FB.sub.w,
where TZL.sub.t is the distance on the optical axis from the object
side surface to the image side surface of the zoom lens at the
telephoto end, FB.sub.t is the back focus of the zoom lens at the
telephoto end expressed in the equivalent air distance, TZL.sub.w
is the distance on the optical axis from the object side surface to
the image side surface of the zoom lens at the wide angle end, and
FB.sub.w is the back focus of the zoom lens at the wide angle end
expressed in the equivalent air distance.
[0108] Conditional expression (14) specifies a preferred range of
the amount of shift of the first positive lens unit. It is
preferred that the amount of shift of the first positive lens unit
be so large that the term in conditional expression (14) has a
value not smaller than the lower limit. Not falling short of the
lower limit of conditional expression (14) helps to reduce the
overall length of the zoom lens at the wide angle end, to reduce
the effective diameter, and to achieve a sufficiently large angle
of view. In the zoom lens according to the later-described
embodiment also, it is preferred that conditional expression (14)
be satisfied.
[0109] In the image pickup apparatus according to this embodiment,
it is preferred that the following conditional expression (15) be
satisfied:
2.0<ME.sub.1Pw/ME.sub.1Nw (15),
where ME.sub.1Pw is the maximum effective diameter of the object
side surface of the first positive lens unit at the wide angle end,
and ME.sub.1Nw is the maximum effective diameter of the object side
surface of the first negative lens unit at the wide angle end.
[0110] It is preferred that the maximum effective diameter of the
first positive lens be so large that the term in conditional
expression (15) has a value not smaller than the lower limit. Not
falling short of the lower limit of conditional expression (15)
helps to achieve an appropriate angle of view at the wide angle end
and appropriate brightness (or speed) at the telephoto end. The
maximum effective diameter refers to the diameter of the bundle of
effective beams on the subject surface, where effective beams refer
to the beams used in forming an image. In the zoom lens according
to the later-described embodiment also, it is preferred that
conditional expression (15) be satisfied.
[0111] In the image pickup apparatus according to this embodiment,
it is preferred that the image side lens unit group include a
focusing lens unit, that during focusing from infinity to a first
extremely close distance, the focusing lens unit move while the
first positive lens unit, the first negative lens unit, and the
second positive lens unit are stationary, and that during focusing
to a second extremely close distance shorter than the first
extremely close distance, the first positive lens unit move toward
the object side while the first negative lens unit and the second
positive lens unit are stationary.
[0112] For focusing from an object at infinity to an object at the
first extremely close distance, it is preferred that a lens unit in
the image side lens unit group be used. More specifically, if the
focusing operation includes focusing onto an object at infinity, it
is preferred that the focusing lens unit be included in the image
side lens unit group and that a lens unit other than the second
positive lens unit be used as a focusing lens unit. This design
helps to reduce the weight of the focusing lens unit. Moreover,
with the reduction in the weight of the focusing lens unit, the
sound generated by the movement of the focusing lens unit can be
reduced. Thus, the reduction in the weight of the focusing lens
unit leads to a reduction in noises generated during video
shooting.
[0113] Advancing the first positive lens unit enables focusing on
an object at a further shorter distance. This distance (second
extremely close distance) is shorter from the image pickup
apparatus than the first extremely close distance. It is preferred
that the direction in which the first positive lens unit is
advanced be the direction toward the object side. While the first
positive lens unit is advanced, the first negative lens and the
second positive lens are stationary.
[0114] It is preferred that the first positive lens have a
sufficiently high refractive power and be configured to have high
optical performance. This further helps to achieve appropriate
magnification in short distance shooting while maintaining high
optical performance. In the zoom lens according to the
later-described embodiment also, it is preferred that this feature
be satisfied. In the case of the zoom lens according to the
later-described embodiment, it is preferred that the focusing lens
unit be the second negative lens unit.
[0115] In the image pickup apparatus according to this embodiment,
it is preferred that focusing to the second extremely close
distance be performed in a certain zoom range (focal length range)
that does not include the telephoto end, and that the first
positive lens unit come closest to the object side when the zoom
lens is focused at infinity at the telephoto end.
[0116] The first positive lens unit is located closer to the object
side at the telephoto end than at the wide angle end. In
consequence, if focusing to an object at the second extremely close
distance is performed at the telephoto end, it is necessary to
further move the first positive lens unit toward the object side.
This will necessitate an increase in the overall length of the
optical system. In view of this, focusing onto an object at the
second close distance be performed in a zoom range (focal length
range) that does not include the telephoto end, namely a zoom range
away from the telephoto end toward the wide angle end. In addition,
it is preferred that the first positive lens unit come closest to
the object side when the zoom lens is focused on an object at
infinity at the telephoto end.
[0117] With the above arrangement, the range of movement of the
first positive lens unit can be made small. Specifically, when the
zoom lens is focused on an object at the second close distance, the
first positive lens unit does not need to come closer to the object
side than its position taken at the time when zoom lens is focused
on an object at infinity at the telephoto end. The above-described
way of moving the first positive lens unit helps to reduce the size
of the optical system.
[0118] In the image pickup apparatus according to this embodiment,
it is preferred that the first positive lens unit include a first
positive lens, a second positive lens arranged closer to the image
side than the first positive lens, and a third positive lens
arranged closer to the image side than the second positive lens and
that the following conditional expression (16) be satisfied:
-1.85<SF.sub.3<SF.sub.2<SF.sub.1<-0.7 (16),
where SF.sub.2=(r.sub.OL1+r.sub.IL1)/(r.sub.OL1-r.sub.IL1),
SF.sub.2=(r.sub.OL2+r.sub.IL2)/(r.sub.OL2-r.sub.IL2), and
SF.sub.3=(r.sub.OL3+r.sub.IL3)/(r.sub.OL3-r.sub.IL3), where
SF.sub.n is the shape factor of the n-th positive lens, r.sub.OLn
is the paraxial radius of curvature of the object side refractive
surface of the n-th positive lens, and r.sub.ILn is the paraxial
radius of curvature of the image side refractive surface of the
n-th positive lens (n=1, 2, 3).
[0119] If the first positive lens unit includes three positive
lenses, the three positive lenses can contribute to the positive
refractive power of the first positive lens unit. Satisfying
conditional expression (16) helps to reduce spherical aberration in
the focal length range near the telephoto end, in which the exit
pupil becomes large. Including three positive lenses in the first
positive lens unit and satisfying conditional expression (16) help
to increase the positive refractive power and while reducing
spherical aberration, in the first positive lens unit.
[0120] It is preferred that the curvature of the image side surface
of the third positive lens be so low (i.e. the radius of curvature
be so large) that the value of SF.sub.3 does not become smaller
than the lower limit of conditional expression (16). Not falling
short of the lower limit of conditional expression (16) helps to
reduce spherical aberration. On the other hand, it is preferred
that the angle of incidence of off-axis beams on the first positive
lens be so small that the value of SF.sub.3 does not become larger
than the upper limit of conditional expression (16). Not exceeding
the upper limit of conditional expression (16) helps to reduce
curvature of field.
[0121] It is preferred that a zoom lens according to an embodiment
include a first positive lens unit having a positive refractive
power located closest to the object side among the lens units in
the zoom lens, a first negative lens unit having a negative
refractive power arranged on the image side of the first positive
lens unit, and an image side lens unit group arranged on the image
side of the first negative lens unit, wherein the first positive
lens unit is located closer to the object side at the telephoto end
than at the wide angle end, the distance between the first negative
lens unit and the first positive lens unit is larger at the
telephoto end than at the wide angle end, the distance between the
image side lens unit group and the first negative lens unit varies
during zooming from the wide angle end to the telephoto end, the
image side lens unit group includes a second positive lens unit
having a positive refractive power and a third positive lens unit
having a positive refractive power and arranged closer to the image
side than the second positive lens unit, the distance between the
second positive lens unit and the first negative lens unit is
smaller at the telephoto end than at the wide angle end, the
distance between the third positive lens unit and the second
positive lens unit varies during zooming from the wide angle end to
the telephoto end, the following conditional expressions (1), (3),
and (A) are satisfied, and the first positive lens unit includes a
plurality of positive lenses, at least one of which satisfies the
following conditional expression (4), and at least one negative
lens:
20<f.sub.t/f.sub.w<60 (1),
0.45<TL.sub.t/f.sub.t<0.70 (3),
90<.nu.d (4), and
S.sub.1P.gtoreq.S.sub.1N.gtoreq.S.sub.2P>S.sub.3P (A),
where f.sub.t is the focal length of the entire zoom lens system at
the telephoto end, f.sub.w is the focal length of the entire zoom
lens system at the wide angle end, TL.sub.t=TZL.sub.t+FB.sub.t,
where TZL.sub.t is the distance on the optical axis from the object
side surface to the image side surface of the zoom lens at the
telephoto end, and FB.sub.t is the back focus of the zoom lens at
the telephoto end expressed in the equivalent air distance, .nu.d
is the Abbe constant with respect to the d-line of the positive
lens in the first positive lens unit, S.sub.1P is the total number
of lenses included in the first positive lens unit, S.sub.1N is the
total number of lenses included in the first negative lens unit,
S.sub.2P is the total number of lenses included in the second
positive lens unit, and S.sub.3P is the total number of lenses
included in the third positive lens unit.
[0122] The technical meaning of the configuration of the zoom lens
according to this embodiment and the conditional expressions
satisfied in the zoom lens according to this embodiment have
already been described in the description of the image pickup
apparatus according to the above-described embodiment. The zoom
lens according to this embodiment may further be characterized by
the preferred features that have been described in connection with
the above-described image pickup apparatus.
[0123] An image pickup apparatus according to an embodiment
includes a zoom lens and an image pickup element that is arranged
on the image side of the zoom lens and has an image pickup surface
to convert an image formed by the zoom lens into an electric
signal. It is preferred that the zoom lens be the zoom lens
according to any one of the above-described embodiments.
[0124] Thus, there can be provided an image pickup apparatus that
is small in size and easy to use in various shooting situations
while having a high zoom ratio or an image pickup apparatus that is
small in size and has an advantageous design in performance
wise.
[0125] In cases where the zoom lens has a lens unit used for
focusing, the above-described features and conditions should be
interpreted as those in the state in which the zoom lens is focused
at infinity. Two or more of the individual features described in
the foregoing may be adopted, where feasible. The conditional
expressions may be applied individually.
[0126] In the above-described zoom lens, the distances between the
lens units vary during zooming. In the above-described zoom lens,
the lens units moves during zooming. In the above-described zoom
lens, during zooming from the wide angle end to the telephoto lens,
the first positive lens unit moves (only) toward the object side,
the second positive lens unit moves (only) toward the object side,
and the third positive lens unit moves (only) toward the image
side. Furthermore, in the above-described zoom lens, the movement
of the first negative zoom lens unit and the second negative lens
unit includes at least partly a movement in which they move once
toward the image side and thereafter toward the object side.
[0127] It is more preferred that the upper and/or lower limit
values in the conditional expressions presented in the foregoing be
further limited as follows in order that the advantages can be
enjoyed more surely.
[0128] In condition (1), it is more preferred that the lower limit
value be 24, still more preferably 27, and the upper limit value be
55, still more preferably 50.
[0129] In condition (2), it is more preferred that the lower limit
value be 34.degree., still more preferably 36.degree., and the
upper limit value be 48.degree., still more preferably
45.degree..
[0130] In condition (3), it is more preferred that the lower limit
value be 0.48, still more preferably 0.5, and the upper limit value
be 0.65, still more preferably 0.6.
[0131] In conditional expression (4), it is preferred that the
lower limit value be 92, still more preferably 94. If an upper
limit is to be set additionally for conditional expression (4), it
is preferred that the upper limit value be 98. Not exceeding this
upper limit will be cost-effective.
[0132] In condition (5), it is more preferred that the lower limit
value be 0.285, and the upper limit value be 0.48.
[0133] In conditional expression (6), it is preferred that the
lower limit value be 98. If an upper limit is to be set
additionally for conditional expression (6), it is preferred that
the upper limit value be 98. Not exceeding this upper limit will be
cost-effective.
[0134] In condition (7), it is more preferred that the lower limit
value be 0.2, still more preferably 0.22, and the upper limit value
be 0.4, still more preferably 0.32.
[0135] In condition (8), it is more preferred that the lower limit
value be -0.05, still more preferably -0.045, and the upper limit
value be -0.025.
[0136] In condition (9), it is more preferred that the lower limit
value be 0.06, and the upper limit value be 0.085, still more
preferably 0.078.
[0137] In condition (10), it is more preferred that the lower limit
value be -0.16, and the upper limit value be -0.105.
[0138] In condition (11), it is more preferred that the lower limit
value be 0.1, and the upper limit value be 0.135.
[0139] In conditional expression (12), it is preferred that the
lower limit value be 0.14, still more preferably 0.15. If an upper
limit is to be set additionally for conditional expression (12), it
is preferred that the upper limit value be 0.3. Not exceeding this
upper limit leads to size reduction of the first positive lens
unit, helping to reduce the overall size of the zoom lens. It is
more preferred that the upper limit value be 0.2.
[0140] In conditional expression (13), it is preferred that the
lower limit value be 1.5, still more preferably 1.8. If an upper
limit is to be set additionally for conditional expression (13), it
is preferred that the upper limit value be 2.5. Not exceeding this
upper limit leads to size reduction of the first positive lens
unit, helping to reduce the overall size of the zoom lens.
[0141] In conditional expression (14), it is preferred that the
lower limit value be 0.5, more preferably 0.55. If an upper limit
is to be set additionally for conditional expression (14), it is
preferred that the upper limit value be 0.9. Not exceeding this
upper limit value helps to make the refractive power of the first
positive lens unit high, facilitating reduction of the size of the
optical system. It is more preferred that the upper limit value be
0.7.
[0142] In conditional expression (15), it is preferred that the
lower limit value be 2.2, still more preferably 2.4. If an upper
limit is to be set additionally for conditional expression (15), it
is preferred that the upper limit value be 3.5. Not exceeding this
upper limit value enables to prevent the negative refractive power
of the first negative lens unit from being necessitated to be
unduly high. This is advantageous for aberration correction. It is
more preferred that the upper limit value be 3.0.
[0143] In condition (16), it is more preferred that the lower limit
value be 0.6, and the upper limit value be 1.7.
[0144] In the above-described image pickup apparatus and zoom lens,
two or more of the above-described features may be adopted. This is
advantageous for achieving better image pickup apparatus. The
preferred features may be adopted in any possible combination. In
the further limitation of the numerical range of the conditional
expressions mentioned above, the further limitation may be made
only to one of the upper limit value and the lower limit value.
[0145] In the following, examples of the zoom lens used in the
image pickup apparatus according to the present invention will be
described in detail with reference to the drawings. It should be
understood that the present invention is by no means limited by the
examples.
[0146] In the following first to eighth examples of the zoom lens
will be described. FIGS. 1A and 1B to 8A to 8B are cross sectional
views of the zoom lens according to the first to eighth examples
respectively. FIGS. 1A, 2A, 3A, 4A, 5A, 6A, 7A, and 8A are cross
sectional views of the zoom lenses at the wide angle end. FIGS. 1B,
2B, 3B, 4B, 5B, 6B, 7B, and 8B are cross sectional views of the
zoom lenses at the telephoto end. All of FIGS. 1A and 1B to 8A to
8B are cross sectional views of the zoom lenses in the state in
which they are focused on an object point at infinity.
[0147] In the cross sectional views, a first lens unit is denoted
by G1, a second lens unit is denoted by G2, an aperture stop is
denoted by S, a third lens unit is denoted by G3, a fourth lens
unit is denoted by G4, a fifth lens unit is denoted by G5, a plane
parallel plate constituting a cover glass of an electronic image
pickup element is denoted by C, and the image plane is denoted by
I. Multi-layer coating for wavelength range restriction may be
applied on the surface of the cover glass C. The cover glass C may
be adapted to have a low-pass filtering function.
[0148] In the following description, the first lens unit G1 has a
positive refractive power and corresponds to the first positive
lens unit. The second lens unit G2 has a negative refractive power
and corresponds to the first negative lens unit. The third lens
unit G3 has a positive refractive power and corresponds to the
second positive lens unit. The fourth lens unit G4 has a negative
refractive power and corresponds to the second negative lens unit.
The fifth lens unit G5 has a positive refractive power and
corresponds to the third positive lens unit. The image side lens
unit group is composed of the third lens unit G3, the fourth lens
unit G4, and the fifth lens unit G5.
[0149] The image pickup element is arranged at the position of the
image plane I. In cases where the image pickup area on the image
pickup element has a substantially rectangular shape, it is
preferred that the image pickup element be arranged in such a way
that the shorter sides of the image pickup area are oriented
substantially parallel to the incidence optical axis of the zoom
lens. Such arrangement is advantageous for reduction in the size of
the zoom lens with respect to the direction of the incidence
optical axis, leading to slimming of the image pickup
apparatus.
[0150] In the zoom lenses according to the first to eighth
examples, the image height at an intermediate focal length and the
image height at the telephoto end are equal to each other, and the
image height at the wide angle end is smaller than them. This is
because the image formed at the wide angle end has a barrel-like
shape, and the image having the barrel-like shape is converted into
an image having a rectangular shape by electrical processing to
correct distortion.
[0151] As shown in FIGS. 1A and 1B, the zoom lens according to the
first example includes, in order from the object side, a first lens
unit G1 having a positive refractive power, a second lens unit G2
having a negative refractive power, a third lens unit G3 having a
positive refractive power, a fourth lens unit G4 having a negative
refractive power, and a fifth lens unit G5 having a positive
refractive power. An aperture stop S is arranged between the second
lens unit G2 and the third lens unit G3.
[0152] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, a positive meniscus lens L3 having a
convex surface directed toward the object side, and a positive
meniscus lens L4 having a convex surface directed toward the object
side.
[0153] The second lens unit G2 is composed of a biconcave negative
lens L5, a biconcave negative lens L6, and a biconvex positive lens
L7.
[0154] The third lens unit G3 is composed of a biconvex positive
lens L8, a negative meniscus lens L9 having a convex surface
directed toward the object side, and a biconvex positive lens L10.
The negative meniscus lens L9 and the biconvex positive lens L10
are cemented together.
[0155] The fourth lens unit G4 is composed of a negative meniscus
lens L11 having a convex surface directed toward the object
side.
[0156] The fifth lens unit G5 is composed of a biconvex positive
lens L12.
[0157] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
image side and thereafter toward the object side.
[0158] The second lens unit G2 is located closer to the object side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0159] There are eight aspheric surfaces, which include both
surfaces of the biconcave negative lens L5, both surfaces of the
biconvex positive lens L8, the image side surface of the biconvex
positive lens L10, the image side surface of the negative meniscus
lens L11, and both surfaces of the biconvex positive lens L12.
[0160] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0161] During focusing to an object at a distance (second close
distance) shorter than the aforementioned close distance (first
close distance), the first lens unit G1 moves along the optical
axis toward the object side, while the second lens unit G2, the
third lens unit G3, the fourth lens unit G4, and the fifth lens
unit G5 are stationary. The zoom lens according to the first
example enables super-macro shooting by advancing (or moving) the
first lens unit G1 toward the object side.
[0162] As shown in FIGS. 2A and 2B, the zoom lens according to the
second example includes, in order from the object side, a first
lens unit G1 having a positive refractive power, a second lens unit
G2 having a negative refractive power, a third lens unit G3 having
a positive refractive power, a fourth lens unit G4 having a
negative refractive power, and a fifth lens unit G5 having a
positive refractive power. An aperture stop S is arranged between
the second lens unit G2 and the third lens unit G3.
[0163] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, and a positive meniscus lens L3 having a
convex surface directed toward the object side.
[0164] The second lens unit G2 is composed of a positive meniscus
lens L4 having a convex surface directed toward the object side, a
biconcave negative lens L5, and a biconvex positive lens L6.
[0165] The third lens unit G3 is composed of a biconvex positive
lens L7, a negative meniscus lens L8 having a convex surface
directed toward the object side, and a biconvex positive lens L9.
The negative meniscus lens L8 and the biconvex positive lens L9 are
cemented together.
[0166] The fourth lens unit G4 is composed of a biconcave negative
lens L10.
[0167] The fifth lens unit G5 is composed of a biconvex positive
lens L11.
[0168] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
image side, thereafter toward the object side, and thereafter
toward the object side. In this way, the fourth lens unit reverses
its direction of movement twice.
[0169] The second lens unit G2 is located closer to the image side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0170] There are six aspheric surfaces, which include both surfaces
of the biconcave negative lens L5, both surfaces of the biconvex
positive lens L7, and both surfaces of the biconvex positive lens
L11.
[0171] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0172] As shown in FIGS. 3A and 3B, the zoom lens according to the
third example includes, in order from the object side, a first lens
unit G1 having a positive refractive power, a second lens unit G2
having a negative refractive power, a third lens unit G3 having a
positive refractive power, a fourth lens unit G4 having a negative
refractive power, and a fifth lens unit G5 having a positive
refractive power. An aperture stop S is arranged between the second
lens unit G2 and the third lens unit G3.
[0173] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, and a positive meniscus lens L3 having a
convex surface directed toward the object side.
[0174] The second lens unit G2 is composed of a biconcave negative
lens L4, a biconcave negative lens L5, and a biconvex positive lens
L6.
[0175] The third lens unit G3 is composed of a biconvex positive
lens L7, a negative meniscus lens L8 having a convex surface
directed toward the object side, and a biconvex positive lens L9.
The negative meniscus lens L8 and the biconvex positive lens L9 are
cemented together.
[0176] The fourth lens unit G4 is composed of a negative meniscus
lens L10 having a convex surface directed toward the object
side.
[0177] The fifth lens unit G5 is composed of a positive meniscus
lens L11 having a convex surface directed toward the image
side.
[0178] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
image side and thereafter toward the object side.
[0179] The second lens unit G2 is located closer to the object side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0180] There are six aspheric surfaces, which include both surfaces
of the biconcave negative lens L5, both surfaces of the biconvex
positive lens L7, and both surfaces of the positive meniscus lens
L11.
[0181] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0182] As shown in FIGS. 4A and 4B, the zoom lens according to the
fourth example includes, in order from the object side, a first
lens unit G1 having a positive refractive power, a second lens unit
G2 having a negative refractive power, a third lens unit G3 having
a positive refractive power, a fourth lens unit G4 having a
negative refractive power, and a fifth lens unit G5 having a
positive refractive power. An aperture stop S is arranged between
the second lens unit G2 and the third lens unit G3.
[0183] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, and a positive meniscus lens L3 having a
convex surface directed toward the object side.
[0184] The second lens unit G2 is composed of a negative meniscus
lens L4 having a convex surface directed toward the object side, a
biconcave negative lens L5, and a biconvex positive lens L6.
[0185] The third lens unit G3 is composed of a positive meniscus
lens L7 having a convex surface directed toward the object side, a
negative meniscus lens L8 having a convex surface directed toward
the object side, and a biconvex positive lens L9. The negative
meniscus lens L8 and the biconvex positive lens L9 are cemented
together.
[0186] The fourth lens unit G4 is composed of a biconcave negative
lens L10.
[0187] The fifth lens unit G5 is composed of a biconvex positive
lens L11.
[0188] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
object side, thereafter toward the image side, and thereafter
toward the object side. In this way, the fourth lens unit reverses
its direction of movement twice.
[0189] The second lens unit G2 is located closer to the image side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0190] There are six aspheric surfaces, which include both surfaces
of the biconcave negative lens L5, both surfaces of the biconvex
positive lens L7, and both surfaces of the positive meniscus lens
L11.
[0191] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0192] As shown in FIGS. 5A and 5B, the zoom lens according to the
fifth example includes, in order from the object side, a first lens
unit G1 having a positive refractive power, a second lens unit G2
having a negative refractive power, a third lens unit G3 having a
positive refractive power, a fourth lens unit G4 having a negative
refractive power, and a fifth lens unit G5 having a positive
refractive power. An aperture stop S is arranged between the second
lens unit G2 and the third lens unit G3.
[0193] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, a positive meniscus lens L3 having a
convex surface directed toward the object side, and a positive
meniscus lens L4 having a convex surface directed toward the object
side.
[0194] The second lens unit G2 is composed of a biconcave negative
lens L5, a biconcave negative lens L6, and a biconvex positive lens
L7.
[0195] The third lens unit G3 is composed of a biconvex positive
lens L8, a negative meniscus lens L9 having a convex surface
directed toward the object side, and a biconvex positive lens L10.
The negative meniscus lens L9 and the biconvex positive lens L10
are cemented together.
[0196] The fourth lens unit G4 is composed of a biconcave negative
lens L11.
[0197] The fifth lens unit G5 is composed of a biconvex positive
lens L12.
[0198] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
image side and thereafter toward the object side.
[0199] The second lens unit G2 is located closer to the object side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0200] There are five aspheric surfaces, which include both
surfaces of the biconcave negative lens L6, both surfaces of the
biconvex positive lens L8, and the object side surface of the
biconvex positive lens L12.
[0201] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0202] As shown in FIGS. 6A and 6B, the zoom lens according to the
six example includes, in order from the object side, a first lens
unit G1 having a positive refractive power, a second lens unit G2
having a negative refractive power, a third lens unit G3 having a
positive refractive power, a fourth lens unit G4 having a negative
refractive power, and a fifth lens unit G5 having a positive
refractive power. An aperture stop S is arranged between the second
lens unit G2 and the third lens unit G3.
[0203] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, a positive meniscus lens L3 having a
convex surface directed toward the object side, and a positive
meniscus lens L4 having a convex surface directed toward the object
side.
[0204] The second lens unit G2 is composed of a biconcave negative
lens L5, a biconcave negative lens L6, and a biconvex positive lens
L7.
[0205] The third lens unit G3 is composed of a biconvex positive
lens L8, a negative meniscus lens L9 having a convex surface
directed toward the object side, and a biconvex positive lens L10.
The negative meniscus lens L9 and the biconvex positive lens L10
are cemented together.
[0206] The fourth lens unit G4 is composed of a negative meniscus
lens L11 having a convex surface directed toward the object
side.
[0207] The fifth lens unit G5 is composed of a biconvex positive
lens L12.
[0208] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side, thereafter toward the
object side, thereafter toward the image side, and thereafter
toward the object side. In this way, the second lens unit reverses
its direction of movement three times. The fourth lens unit G4
moves first toward the image side and thereafter toward the object
side.
[0209] The second lens unit G2 is located closer to the object side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0210] There are eight aspheric surfaces, which include both
surfaces of the biconcave negative lens L5, both surfaces of the
biconvex positive lens L8, the image side surface of the biconvex
positive lens L10, the image side surface of the negative meniscus
lens L11, and both surfaces of the biconvex positive lens L12.
[0211] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0212] As shown in FIGS. 7A and 7B, the zoom lens according to the
seventh example includes, in order from the object side, a first
lens unit G1 having a positive refractive power, a second lens unit
G2 having a negative refractive power, a third lens unit G3 having
a positive refractive power, a fourth lens unit G4 having a
negative refractive power, and a fifth lens unit G5 having a
positive refractive power. An aperture stop S is arranged between
the second lens unit G2 and the third lens unit G3.
[0213] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, a positive meniscus lens L3 having a
convex surface directed toward the object side, and a positive
meniscus lens L4 having a convex surface directed toward the object
side.
[0214] The second lens unit G2 is composed of a biconcave negative
lens L5, a biconcave negative lens L6, and a biconvex positive lens
L7.
[0215] The third lens unit G3 is composed of a biconvex positive
lens L8, a negative meniscus lens L9 having a convex surface
directed toward the object side, and a biconvex positive lens L10.
The negative meniscus lens L9 and the biconvex positive lens L10
are cemented together.
[0216] The fourth lens unit G4 is composed of a negative meniscus
lens L11 having a convex surface directed toward the object
side.
[0217] The fifth lens unit G5 is composed of a biconvex positive
lens L12 and a negative meniscus lens L13 having a convex surface
directed toward the image side.
[0218] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
image side and thereafter toward the object side.
[0219] The second lens unit G2 is located closer to the object side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0220] There are eight aspheric surfaces, which include both
surfaces of the biconcave negative lens L5, both surfaces of the
biconvex positive lens L8, the image side surface of the biconvex
positive lens L10, the image side surface of the negative meniscus
lens L11, and both surfaces of the biconvex positive lens L12.
[0221] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0222] As shown in FIGS. 8A and 8B, the zoom lens according to the
eighth example includes, in order from the object side, a first
lens unit G1 having a positive refractive power, a second lens unit
G2 having a negative refractive power, a third lens unit G3 having
a positive refractive power, a fourth lens unit G4 having a
negative refractive power, and a fifth lens unit G5 having a
positive refractive power. An aperture stop S is arranged between
the second lens unit G2 and the third lens unit G3.
[0223] The first lens unit G1 is composed of a negative meniscus
lens L1 having a convex surface directed toward the object side, a
biconvex positive lens L2, a positive meniscus lens L3 having a
convex surface directed toward the object side, and a positive
meniscus lens L4 having a convex surface directed toward the object
side.
[0224] The second lens unit G2 is composed of a biconcave negative
lens L5, a biconcave negative lens L6, and a biconvex positive lens
L7.
[0225] The third lens unit G3 is composed of a biconvex positive
lens L8, a negative meniscus lens L9 having a convex surface
directed toward the object side, and a biconvex positive lens L10.
The negative meniscus lens L9 and the biconvex positive lens L10
are cemented together.
[0226] The fourth lens unit G4 is composed of a plano-concave
negative lens L11 and a positive meniscus lens L12 having a convex
surface directed toward the object side.
[0227] The fifth lens unit G5 is composed of a biconvex positive
lens L13 and a negative meniscus lens L14 having a convex surface
directed toward the image side.
[0228] During zooming from the wide angle end to the telephoto end,
the first lens unit G1 moves only toward the object side, the
second lens unit G2 moves, the aperture stop S moves with the third
lens unit G3, the third lens unit G3 moves only toward the object
side, the fourth lens unit G4 moves, and the fifth lens unit G5
moves only toward the image side. Specifically, the second lens
unit G2 moves first toward the image side and thereafter toward the
object side, and the fourth lens unit G4 moves first toward the
image side and thereafter toward the object side.
[0229] The second lens unit G2 is located closer to the object side
at the telephoto end than at the wide angle end. The fourth lens
unit G4 is located closer to the object side at the telephoto end
than at the wide angle end.
[0230] There are eight aspheric surfaces, which include both
surfaces of the biconcave negative lens L5, both surfaces of the
biconvex positive lens L8, the image side surface of the biconvex
positive lens L10, the image side surface of the positive meniscus
lens L12, and both surfaces of the biconvex positive lens L13.
[0231] During focusing from an object at infinity to an object at
an extremely close distance (first extremely close distance), the
fourth lens unit G4 moves along the optical axis toward the image
side, while the first lens unit G1, the second lens unit G2, the
third lens unit G3, and the fifth lens unit G5 are stationary.
[0232] In the following, numerical data of the zoom lenses
according to the examples will be presented. In the numerical data
of the examples, the radius of curvature r of each lens surface,
the distance d between adjacent lenses, the refractive index nd
with respect to the d-line of each lens, and the Abbe constant .nu.
of each lens are presented. The lens surfaces having a surface
number with an asterisk "*" are aspheric surfaces. In the zoom
data, f represents the focal length of the entire zoom lens system,
FNO. represents the F-number, .omega. represents the half angle of
view, IH represents the image height, and FB represents the back
focus. In the following data, "overall length" is the sum of the
distance from the lens surface closest to the object side to the
lens surface closest to the image side in the zoom lens and the
back focus FB. The focal lengths f1, f2, . . . of the respective
lens units will also be presented. The back focus FB is the
distance from the last lens surface to the paraxial image plane,
expressed in the equivalent air distance.
[0233] Zoom data is given for the wide angle end (wide angle), a
first intermediate focal length state (intermediate 1), a second
intermediate focal length state (intermediate 2), a third
intermediate focal length state (intermediate 3), and the telephoto
end (telephoto). The first intermediate focal length state is a
focal length state between the wide angle end and the second
intermediate focal length state, and the third intermediate focal
length state is a focal length state between the second focal
length state and the telephoto end. During actual zooming from the
wide angle end to the telephoto end, the focal length varies in
order of the wide angle end, the first intermediate focal length
state, the second intermediate focal length state, the third
intermediate focal length state, and the telephoto end.
[0234] In the numerical data of the first example, various data is
presented also for the state in which the zoom lens is focused on
an object at the second extremely close distance (in the
super-macro state), where Pos1 is numerical data for the first
macro shooting, and Pos 2 is numerical data for the second macro
shooting. In this connection, the "extremely close distance" refers
to the distance from the lens surface closest to the object side to
the object.
[0235] Numerical data of each embodiment described above is shown
below. Apart from symbols described above, f denotes a focal length
of the entire zoom lens system, F.sub.NO denotes an F number,
.omega. denotes a half angle of field, WE denotes a wide angle end,
ST denotes an intermediate state, TE denotes a telephoto end, each
of r1, r2, . . . denotes radius of curvature of each lens surface,
each of d1, d2, . . . denotes a distance between two lenses, each
of nd1, nd2, . . . denotes a refractive index of each lens for a
d-line, and each of .nu.d1, .nu.d2, . . . denotes an Abbe constant
for each lens. Further, * denotes an aspheric data, ER denotes an
effective radius.
[0236] The overall length of the lens system which will be
described later is a length which is obtained by adding the back
focus to a distance from the first lens surface up to the last lens
surface. fb (back focus) is a unit which is expressed upon air
conversion of a distance from the last lens surface up to a
paraxial image plane.
[0237] When z is let to be an optical axis with a direction of
traveling of light as a positive (direction), and y is let to be in
a direction orthogonal to the optical axis, a shape of the aspheric
surface is described by the following expression.
z=(y.sup.2/r)/[1+{1-(k+1)(y/r).sup.2}.sup.1/2]+A4y.sup.4+A6y.sup.6+A8y.s-
up.8+A10y.sup.10+A12y.sup.12
where, r denotes a paraxial radius of curvature, K denotes a
conical coefficient, A4, A6, A8, A10, and A12 denote aspherical
surface coefficients of a fourth order, a sixth order, an eight
order, a tenth order, and a twelfth order respectively. Moreover,
in the aspherical surface coefficients, `e-n` (where, n is an
integral number) indicates `10.sup.-n`.
Example 1
TABLE-US-00001 [0238] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 76.873 1.00 1.91082 35.25 2 36.739
0.15 3 38.956 2.99 1.49700 81.54 4 -2000.000 0.10 5 34.300 3.03
1.43875 94.93 6 330.559 0.10 7 28.995 3.02 1.43875 94.93 8 141.577
Variable 9* -24.654 0.40 1.86400 40.58 10* 8.060 2.10 11 -9.985
0.45 1.72916 54.68 12 18.498 0.53 13 20.394 1.45 1.94595 17.98 14
-39.429 Variable 15(stop) .infin. 0.66 16* 6.685 2.61 1.58313 59.46
17* -29.666 0.97 18 34.318 0.84 1.91082 35.25 19 5.081 2.86 1.48749
70.23 20* -13.096 Variable 21 93.325 0.61 1.49700 81.54 22* 11.774
Variable 23* 28.818 1.56 1.49710 81.56 24* -14.158 Variable 25
.infin. 1.00 1.51633 64.14 26 .infin. 0.40 Image plane .infin.
(Image pickup surface) Aspherical surface data 9th surface k =
0.000 A4 = 5.74403e-04, A6 = -4.41207e-06, A8 = -2.04129e-07, A10 =
5.25599e-09 10th surface k = 0.000 A4 = 4.10529e-04, A6 =
1.10341e-05, A8 = -5.97778e-07, A10 = 2.66856e-08 16th surface k =
0.000 A4 = -3.21650e-04, A6 = -1.38221e-06, A8 = -9.01321e-08, A10
= 1.12360e-09 17th surface k = 0.000 A4 = 2.55310e-04, A6 =
-1.09852e-06, A8 = 2.89590e-08, A10 = 1.84211e-09 20th surface k =
0.000 A4 = -6.64184e-05, A6 = -4.11923e-06, A8 = 7.14519e-08, A10 =
-1.70739e-08 22th surface k = 0.000 A4 = -3.35472e-05, A6 =
8.42006e-06, A8 = -7.30402e-07, A10 = 4.38207e-08 23th surface k =
0.000 A4 = -1.15495e-04, A6 = 3.93790e-05, A8 = -5.08278e-07, A10 =
2.28220e-08 24th surface k = 0.000 A4 = 1.24798e-04, A6 =
3.84628e-05 Zoom data Wide angle Intermediate2 Telephoto Focal
length 4.55 28.21 174.87 Fno. 3.88 5.00 6.83 IH 3.39 3.86 3.86
2.omega. 82.1 15.0 2.5 fb(in air) 8.53 4.37 2.46 Lens total
length(in air) 56.44 75.62 94.73 d8 0.49 20.01 29.32 d14 16.94 6.33
0.50 d20 2.57 15.71 9.43 d22 2.48 3.76 27.59 d24 7.47 3.31 1.40
Intermediate1 Intermediate3 Focal length 11.33 70.23 Fno. 4.40 6.10
IH 3.86 3.86 2.omega. 36.6 6.1 fb(in air) 6.53 2.77 Lens total
length(in air) 61.95 82.53 d8 7.43 26.93 d14 8.61 3.96 d20 12.35
13.66 d22 1.60 9.77 d24 5.47 1.71 Unit focal length f1 = 42.69 f2 =
-5.51 f3 = 11.48 f4 = -27.18 f5 = 19.33 Space data at super macro
Pos1 Pos2 Extremely close distance 192.558 295.137 Magnification
0.136 0.1963 Focal length 47.49 117.51 Fno. 4.27 4.60 2.omega. 7.97
2.95 fb(in air) 4.37 2.83 Lens total length(in air) 83.06 87.26 d8
27.46 31.61 d14 6.33 3.96 d20 18.96 21.01 d22 0.51 2.43 d24 3.24
1.64 d27 0.08 0.13
Example 2
TABLE-US-00002 [0239] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 54.790 1.00 1.88300 40.76 2 21.924
0.10 3 22.233 3.55 1.43875 94.93 4 -104.089 0.15 5 20.468 2.93
1.59282 68.63 6 194.731 Variable 7 40.248 0.40 1.88300 40.76 8
5.841 2.63 9* -7.633 0.45 1.74156 49.21 10* 29.063 0.45 11 22.920
1.46 1.94595 17.98 12 -30.990 Variable 13(stop) .infin. 0.66 14*
5.675 1.99 1.58313 59.46 15* -366.065 0.50 16 14.038 0.82 1.91082
35.25 17 4.048 2.40 1.48749 70.23 18 -13.571 Variable 19 -35.830
0.43 1.51633 64.14 20 9.415 Variable 21* 25.415 1.69 1.49710 81.56
22* -12.042 Variable 23 .infin. 1.00 1.51633 64.14 24 .infin. 0.40
Image plane .infin. (Image pickup surface) Aspherical surface data
9th surface k = 0.000 A4 = 4.22776e-04, A6 = -5.36808e-05, A8 =
4.37478e-06, A10 = -1.06838e-07 10th surface k = 0.000 A4 =
3.22877e-04, A6 = -5.49769e-05, A8 = 4.74077e-06, A10 =
-1.21176e-07 14th surface k = 0.000 A4 = -1.41008e-04, A6 =
-1.53643e-05, A8 = 2.73442e-07, A10 = 3.23009e-09 15th surface k =
0.000 A4 = 5.45234e-04, A6 = -1.85978e-05, A8 = 6.46690e-07, A10 =
3.43566e-09 21th surface k = 0.000 A4 = -3.24708e-04, A6 =
8.45115e-06, A8 = -1.60315e-07, A10 = 5.05996e-09 22th surface k =
0.000 A4 = -1.62401e-04, A6 = 7.96280e-06, A8 = -1.93649e-07, A10 =
5.85825e-09 Zoom data Wide angle Intermediate2 Telephoto Focal
length 4.55 24.41 130.99 Fno. 3.08 5.15 6.91 IH 3.53 4.16 4.16
2.omega. 83.1 18.5 3.6 fb(in air) 8.46 5.75 2.46 Lens total
length(in air) 53.23 63.83 78.08 d6 0.34 15.18 26.33 d12 17.28 4.89
0.50 d18 2.26 11.22 7.33 d20 3.27 5.17 19.85 d22 7.41 4.69 1.40
Intermediate1 Intermediate3 Focal length 10.54 56.55 Fno. 4.05 6.40
IH 4.16 4.16 2.omega. 42.5 8.3 fb(in air) 7.76 2.89 Lens total
length(in air) 54.43 72.53 d6 3.80 21.77 d12 8.26 3.46 d18 6.77
10.54 d20 6.22 12.26 d22 6.70 1.83 Unit focal length f1 = 38.14 f2
= -5.60 f3 = 9.89 f4 = -14.39 f5 = 16.69
Example 3
TABLE-US-00003 [0240] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 42.672 1.00 1.91082 35.25 2 24.799
0.13 3 24.640 4.65 1.49700 81.54 4 -251.690 0.15 5 24.626 3.60
1.49700 81.54 6 169.568 Variable 7 -133.765 0.40 1.88300 40.76 8
6.757 2.27 9* -8.308 0.45 1.74156 49.21 10* 25.509 0.48 11 19.169
1.48 1.94595 17.98 12 -40.121 Variable 13(stop) .infin. 0.66 14*
6.549 2.76 1.58313 59.46 15* -38.493 0.58 16 23.270 1.05 1.91082
35.25 17 4.859 2.68 1.48749 70.23 18 -14.732 Variable 19 36.768
0.62 1.51633 64.14 20 10.070 Variable 21* -35.811 2.20 1.49710
81.56 22* -8.092 Variable 23 .infin. 1.00 1.51633 64.14 24 .infin.
0.40 Image plane .infin. (Image pickup surface) Aspherical surface
data 9th surface k = 0.000 A4 = 6.34015e-04, A6 = 2.18875e-05, A8 =
-3.31401e-06, A10 = 1.17218e-07 10th surface k = 0.000 A4 =
5.72573e-04, A6 = 6.94117e-07, A8 = -2.13581e-06, A10 = 8.95311e-08
14th surface k = 0.000 A4 = -3.39715e-04, A6 = 5.64902e-06, A8 =
-4.89183e-07, A10 = 2.47289e-09 15th surface k = 0.000 A4 =
1.97393e-04, A6 = 9.37210e-06, A8 = -7.55161e-07, A10 = 1.29566e-08
21th surface k = 0.000 A4 = -6.83520e-04, A6 = -3.97071e-06, A8 =
1.65522e-06, A10 = -7.97399e-08 22th surface k = 0.000 A4 =
-2.86777e-04, A6 = 4.09813e-06, A8 = 8.99804e-07, A10 =
-4.54312e-08 Zoom data Wide angle Intermediate2 Telephoto Focal
length 4.55 28.21 174.87 Fno. 3.88 5.00 6.88 IH 3.53 4.16 4.16
2.omega. 85.0 16.1 2.8 fb(in air) 9.40 5.55 2.46 Lens total
length(in air) 56.23 75.51 92.23 d6 0.48 19.34 28.61 d12 17.31 7.16
0.50 d18 1.47 9.32 5.42 d20 2.42 9.00 30.10 d22 8.34 4.49 1.40
Intermediate1 Intermediate3 Focal length 11.33 70.23 Fno. 4.40 6.10
IH 4.16 4.16 2.omega. 39.0 6.8 fb(in air) 7.68 1.89 Lens total
length(in air) 61.37 81.23 d6 6.73 25.38 d12 9.02 4.44 d18 8.42
10.37 d20 4.38 14.01 d22 6.62 0.83 Unit focal length f1 = 41.79 f2
= -5.55 f3 = 11.13 f4 = -27.07 f5 = 20.49
Example 4
TABLE-US-00004 [0241] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 38.921 1.00 1.91082 35.25 2 22.847
0.10 3 22.675 3.36 1.49700 81.54 4 -296.725 0.15 5 21.419 2.57
1.49700 81.54 6 91.753 Variable 7 82.949 0.40 1.88300 40.76 8 5.785
2.45 9* -8.940 0.45 1.74156 49.21 10* 34.684 0.38 11 19.397 1.45
1.94595 17.98 12 -45.810 Variable 13(stop) .infin. 0.66 14* 5.868
2.07 1.58313 59.46 15* 412.402 0.67 16 14.034 0.83 1.91082 35.25 17
4.227 2.37 1.48749 70.23 18 -13.284 Variable 19 -47.610 0.44
1.51633 64.14 20 9.092 Variable 21* 24.494 1.75 1.49710 81.56 22*
-11.958 Variable 23 .infin. 1.00 1.51633 64.14 24 .infin. 0.40
Image plane .infin. (Image pickup surface) Aspherical surface data
9th surface k = 0.000 A4 = 4.49114e-05, A6 = 2.58363e-05, A8 =
-1.57823e-06, A10 = 3.43855e-08 10th surface k = 0.000 A4 =
1.99078e-05, A6 = 1.62937e-05, A8 = -1.13964e-06, A10 = 2.86830e-08
14th surface k = 0.000 A4 = -2.13179e-04, A6 = -2.53479e-06, A8 =
-1.57084e-07, A10 = 5.02378e-09 15th surface k = 0.000 A4 =
4.14668e-04, A6 = -1.19363e-07, A8 = -2.29816e-07, A10 =
1.45490e-08 21th surface k = 0.000 A4 = -5.00222e-04, A6 =
4.67885e-05, A8 = -2.38442e-06, A10 = 7.57654e-08 22th surface k =
0.000 A4 = -3.81892e-04, A6 = 5.45636e-05, A8 = -2.86603e-06, A10 =
8.75631e-08 Zoom data Wide angle Intermediate2 Telephoto Focal
length 4.55 24.41 131.01 Fno. 2.81 4.69 7.04 IH 3.53 4.16 4.16
2.omega. 82.8 18.5 3.6 fb(in air) 8.55 5.16 2.46 Lens total
length(in air) 53.23 63.83 78.08 d6 0.32 14.97 26.64 d12 18.05 5.36
0.50 d18 2.12 11.35 8.81 d20 3.10 5.89 18.58 d22 7.09 3.70 1.00 d25
0.40 0.40 0.40 Intermediate1 Intermediate3 Focal length 10.54 56.55
Fno. 3.94 6.09 IH 4.16 4.16 2.omega. 42.3 8.3 fb(in air) 6.85 2.68
Lens total length(in air) 53.65 72.28 d6 3.89 21.84 d12 8.80 3.52
d18 7.25 11.58 d20 5.77 11.55 d22 5.39 1.23 d25 0.40 0.40 Unit
focal length f1 = 40.04 f2 = -5.72 f3 = 10.10 f4 = -14.75 f5 =
16.43
Example 5
TABLE-US-00005 [0242] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 81.806 1.00 1.91082 35.25 2 36.191
0.10 3 37.061 3.19 1.49700 81.54 4 -498.419 0.10 5 35.000 2.91
1.45600 90.28 6 290.553 0.10 7 27.700 3.00 1.45600 90.28 8 114.422
Variable 9 -71.570 0.40 1.88300 40.76 10 7.630 1.98 11* -10.161
0.45 1.74156 49.21 12* 11.909 0.69 13 17.463 1.50 1.94595 17.98 14
-43.852 Variable 15(stop) .infin. 0.66 16* 6.138 2.46 1.58313 59.46
17* -96.248 0.77 18 20.534 0.80 1.91082 35.25 19 4.640 2.77 1.48749
70.23 20 -14.090 Variable 21 -105.171 0.62 1.51633 64.14 22 15.733
Variable 23* 66.048 1.55 1.49710 81.56 24 -11.578 Variable 25
.infin. 1.00 1.51633 64.14 26 .infin. 0.40 Image plane .infin.
(Image pickup surface) Aspherical surface data 11th surface k =
0.000 A4 = 4.85772e-04, A6 = -1.06983e-06, A8 = -4.38703e-07, A10 =
9.23372e-09 12th surface k = 0.000 A4 = 1.96415e-04, A6 =
-1.07949e-05 16th surface k = 0.000 A4 = -3.22634e-04, A6 =
-2.20402e-06, A8 = -1.74689e-08, A10 = -5.39377e-09 17th surface k
= 0.000 A4 = 2.44920e-04 23th surface k = 0.000 A4 = -2.72542e-04,
A6 = -1.66190e-07 Zoom data Wide angle Intermediate2 Telephoto
Focal length 4.55 28.21 174.88 Fno. 3.88 5.00 6.88 IH 3.53 4.16
4.16 2.omega. 86.1 16.0 2.7 fb(in air) 10.11 5.60 2.45 Lens total
length(in air) 56.23 74.23 92.72 d8 0.41 19.39 28.29 d14 16.73 6.27
0.50 d20 0.80 13.40 6.83 d22 3.13 4.51 29.60 d24 9.05 4.54 1.40
Intermediate1 Intermediate3 Focal length 11.33 70.23 Fno. 4.40 6.10
IH 4.16 4.16 2.omega. 39.1 6.6 fb(in air) 7.96 3.11 Lens total
length(in air) 61.79 81.23 d8 8.17 25.65 d14 8.79 3.98 d20 9.67
11.89 d22 2.15 11.54 d24 6.90 2.05 Unit focal length f1 = 41.26 f2
= -5.47 f3 = 11.19 f4 = -26.46 f5 = 19.95
Example 6
TABLE-US-00006 [0243] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 76.944 1.00 1.91082 35.25 2 36.940
0.10 3 38.129 3.37 1.49700 81.54 4 -2000.000 0.10 5 36.915 3.38
1.43875 94.93 6 525.263 0.10 7 29.122 3.30 1.43875 94.93 8 139.806
Variable 9* -28.378 0.43 1.86400 40.58 10* 8.375 2.11 11 -9.529
0.45 1.72916 54.68 12 17.272 0.57 13 21.139 1.45 1.94595 17.98 14
-37.154 Variable 15(stop) .infin. 0.66 16* 7.260 2.85 1.58313 59.46
17* -20.028 1.05 18 59.130 1.00 1.91082 35.25 19 5.387 3.10 1.48749
70.23 20* -12.788 Variable 21 66.179 0.76 1.49700 81.54 22* 11.681
Variable 23* 25.830 1.94 1.49710 81.56 24* -14.918 Variable 25
.infin. 1.00 1.51633 64.14 26 .infin. 0.40 Image plane .infin.
(Image pickup surface) Aspherical surface data 9th surface k =
0.000 A4 = 5.33768e-04, A6 = -4.52696e-06, A8 = -7.06370e-08, A10 =
2.17837e-09 10th surface k = 0.000 A4 = 3.65845e-04, A6 =
9.26416e-06, A8 = -4.97531e-07, A10 = 3.59183e-08 16th surface k =
0.000 A4 = -3.15331e-04, A6 = -2.12781e-06, A8 = -2.36001e-07, A10
= 1.25714e-08 17th surface k = 0.000 A4 = 2.81533e-04, A6 =
-8.19928e-06, A8 = 2.16359e-07, A10 = 7.26872e-09 20th surface k =
0.000 A4 = -1.88851e-04, A6 = 4.57536e-06, A8 = -7.26281e-07, A10 =
-4.62290e-09 22th surface k = 0.000 A4 = -1.22024e-05, A6 =
2.53700e-06, A8 = 1.88302e-07, A10 = -1.39628e-08 23th surface k =
0.000 A4 = -2.90471e-04, A6 = 1.30652e-05, A8 = -1.37328e-07, A10 =
1.30885e-09 24th surface k = 0.000 A4 = -9.84317e-05, A6 =
8.99929e-06 Zoom data Wide angle Intermediate2 Telephoto Focal
length 4.55 28.21 174.87 Fno. 3.88 5.00 6.40 IH 3.53 4.16 4.16
2.omega. 84.8 16.0 2.7 fb(in air) 9.63 5.39 2.46 Lens total
length(in air) 59.23 78.73 95.33 d8 0.44 19.92 29.43 d14 17.47 6.70
0.50 d20 0.80 14.91 8.99 d22 3.17 4.08 26.23 d24 8.57 4.33 1.40
Intermediate1 Intermediate3 Focal length 11.33 70.23 Fno. 4.40 6.10
IH 4.16 4.16 2.omega. 39.2 6.6 fb(in air) 7.79 3.08 Lens total
length(in air) 65.04 84.73 d8 7.87 26.85 d14 9.07 4.03 d20 10.90
14.94 d22 1.68 8.11 d24 6.73 2.02 Unit focal length f1 = 43.01 f2 =
-5.57 f3 = 11.90 f4 = -28.67 f5 = 19.33
Example 7
TABLE-US-00007 [0244] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 77.370 1.00 1.91082 35.25 2 37.006
0.13 3 38.955 3.00 1.49700 81.54 4 -2000.000 0.10 5 34.434 3.03
1.43875 94.93 6 343.788 0.10 7 28.937 2.97 1.43875 94.93 8 125.948
Variable 9* -29.340 0.40 1.86400 40.58 10* 7.822 2.10 11 -9.841
0.45 1.72916 54.68 12 18.193 0.54 13 20.934 1.45 1.94595 17.98 14
-38.153 Variable 15(stop) .infin. 0.50 16* 6.678 2.62 1.58313 59.46
17* -28.041 0.79 18 28.952 0.80 1.91082 35.25 19 4.989 2.86 1.48749
70.23 20* -14.515 Variable 21 486.610 0.58 1.49700 81.54 22* 12.431
Variable 23* 20.359 1.71 1.49710 81.56 24* -13.318 0.12 25 -21.300
0.36 1.80440 39.59 26 -27.293 Variable 27 .infin. 1.00 1.51633
64.14 28 .infin. 0.40 Image plane .infin. (Image pickup surface)
Aspherical surface data 9th surface k = 0.000 A4 = 4.75888e-04, A6
= -4.84163e-06, A8 = -4.61247e-08, A10 = 1.91567e-09 10th surface k
= 0.000 A4 = 3.05511e-04, A6 = 7.96439e-06, A8 = -4.67707e-07, A10
= 3.18936e-08 16th surface k = 0.000 A4 = -3.40099e-04, A6 =
-1.19695e-06, A8 = -1.11057e-07, A10 = 1.97228e-09 17th surface k =
0.000 A4 = 2.42137e-04, A6 = -1.18219e-06, A8 = 4.72774e-08, A10 =
1.98463e-09 20th surface k = 0.000 A4 = -1.02403e-04, A6 =
-3.30056e-06, A8 = -2.57322e-08, A10 = -1.85061e-08 22th surface k
= 0.000 A4 = -2.29882e-05, A6 = 3.20844e-06, A8 = -2.47246e-08, A10
= 1.22198e-08 23th surface k = 0.000 A4 = 1.43207e-04, A6 =
-1.90161e-05, A8 = 1.31754e-06, A10 = -2.63736e-08 24th surface k =
0.000 A4 = 3.75312e-04, A6 = -3.36777e-06 Zoom data Wide angle
Intermediate2 Telephoto Focal length 4.55 28.21 174.87 Fno. 3.88
5.00 6.83 IH 3.53 4.16 4.16 2.omega. 85.4 16.1 2.7 fb(in air) 8.62
4.81 2.46 Lens total length(in air) 56.93 75.70 94.73 d8 0.46 20.16
29.59 d14 17.18 6.25 0.50 d20 1.83 15.23 10.36 d22 3.22 3.64 26.19
d26 7.56 3.75 1.40 Intermediate1 Intermediate3 Focal length 11.33
70.23 Fno. 4.40 6.10 IH 4.16 4.16 2.omega. 39.1 6.6 fb(in air) 7.00
2.46 Lens total length(in air) 62.49 82.53 d8 8.62 26.98 d14 8.87
3.80 d20 10.94 14.97 d22 1.44 8.69 d26 5.94 1.40 Unit focal length
f1 = 43.12 f2 = -5.52 f3 = 11.34 f4 = -25.68 f5 = 19.03
Example 8
TABLE-US-00008 [0245] Unit mm Surface data Surface no. r d nd .nu.d
Object plane .infin. .infin. 1 76.797 1.00 1.91082 35.25 2 36.937
0.14 3 38.956 2.99 1.49700 81.54 4 -2000.000 0.10 5 34.300 3.03
1.43875 94.93 6 330.561 0.10 7 29.129 2.95 1.43875 94.93 8 127.943
Variable 9* -29.431 0.40 1.86400 40.58 10* 7.934 2.13 11 -9.728
0.45 1.72916 54.68 12 18.262 0.54 13 21.117 1.44 1.94595 17.98 14
-38.768 Variable 15(stop) .infin. 0.50 16* 6.776 2.61 1.58313 59.46
17* -26.062 0.90 18 31.424 0.80 1.91082 35.25 19 5.051 2.86 1.48749
70.23 20* -14.050 Variable 21 .infin. 0.40 1.49700 81.54 22 8.768
0.11 23 9.300 0.44 1.51633 64.14 24* 13.721 Variable 25* 21.004
1.76 1.49710 81.56 26* -11.279 0.12 27 -21.300 0.36 1.80440 39.59
28 -34.360 Variable 29 .infin. 1.00 1.51633 64.14 30 .infin. 0.40
Image plane .infin. (Image pickup surface) Aspherical surface data
9th surface k = 0.000 A4 = 4.76328e-04, A6 = -4.27053e-06, A8 =
-2.38538e-08, A10 = 1.22320e-09 10th surface k = 0.000 A4 =
3.12905e-04, A6 = 8.26113e-06, A8 = -5.12817e-07, A10 = 4.04000e-08
16th surface k = 0.000 A4 = -3.31610e-04, A6 = -1.54498e-06, A8 =
-1.23895e-07, A10 = 3.08278e-09 17th surface k = 0.000 A4 =
2.55408e-04, A6 = -2.20119e-06, A8 = 6.28543e-08, A10 = 2.29430e-09
20th surface k = 0.000 A4 = -1.17194e-04, A6 = -2.80936e-06, A8 =
-1.04559e-07, A10 = -1.75334e-08 24th surface k = 0.000 A4 =
-3.05045e-05, A6 = 6.39706e-06, A8 = -4.80035e-07, A10 =
2.54192e-08 25th surface k = 0.000 A4 = -1.73738e-04, A6 =
2.41050e-05, A8 = -8.73902e-07, A10 = 2.56806e-08 26th surface k =
0.000 A4 = 1.13879e-04, A6 = 2.90597e-05, A8 = -1.20098e-06, A10 =
2.77084e-08 Zoom data Wide angle Intermediate2 Telephoto Focal
length 4.55 28.21 174.87 Fno. 3.88 5.00 6.83 IH 3.53 4.16 4.16
2.omega. 85.1 16.1 2.7 fb(in air) 8.71 4.70 2.46 Lens total
length(in air) 56.91 76.01 95.03 d8 0.45 20.15 29.59 d14 17.04 6.31
0.50 d20 1.62 15.00 10.46 d24 2.94 3.71 25.88 d28 7.65 3.64 1.40
Intermediate1 Intermediate3 Focal length 11.33 70.23 Fno. 4.40 6.10
IH 4.16 4.16 2.omega. 39.1 6.6 fb(in air) 6.98 2.46 Lens total
length(in air) 62.70 82.83 d8 8.49 26.96 d14 8.85 3.78 d20 10.80
15.10 d24 1.44 8.39 d28 5.92 1.40 Unit focal length f1 = 43.14 f2 =
-5.50 f3 = 11.37 f4 = -25.85 f5 = 19.04
[0246] FIGS. 9A to 9L, 10A to 10L, 11A to 11L, 12A to 12L, 13A to
13L, 14A to 14L, 15A to 15L, and 16A to 16L are aberration diagrams
of the zoom lenses according to the first to eighth examples in the
state in which the zoom lenses are focused on an object at
infinity. In these diagrams, "FIY" represents the largest image
height.
[0247] Among these aberration diagrams, FIGS. 9A, 10A, 11A, 12A,
13A, 14A, 15A, and 16A show spherical aberration (SA) at the wide
angle end, FIGS. 9B, 10B, 11B, 12B, 13B, 14B, 15B, and 16B show
astigmatism (SA) at the wide angle end, FIGS. 9C, 10C, 11C, 12C,
13C, 14C, 15C, and 16C show distortion (DT) at the wide angle end,
and FIGS. 9D, 10D, 11D, 12D, 13D, 14D, 15D, and 16D show chromatic
aberration of magnification (CC) at the wide angle end.
[0248] FIGS. 9E 10E, 11E, 12E, 13E, 14E, 15E, and 16E show
spherical aberration (SA) in the first intermediate focal length
state, FIGS. 9F, 10F, 11F, 12F, 13F, 14F, 15F, and 16F show
astigmatism (SA) in the first intermediate focal length state,
FIGS. 9G, 10G, 11G, 12G, 13G, 14G, 15G, and 16G show distortion
(DT) in the first intermediate focal length state, and FIGS. 9H,
10H, 11H, 12H, 13H, 14H, 15H, and 16H show chromatic aberration of
magnification (CC) in the first intermediate focal length
state.
[0249] FIGS. 9I, 10I, 11I, 12I, 13I, 14I, 15I, and 16I show
spherical aberration (SA) at the telephoto end, FIGS. 9J, 10J, 11J,
12J, 13J, 14J, 15J, and 16J show astigmatism (SA) at the telephoto
end, FIGS. 9K, 10K, 11K, 12K, 13K, 14K, 15K, and 16K show
distortion (DT) at the telephoto end, and FIGS. 9L, 10L, 11L, 12L,
13L, 14L, 15L, and 16L show chromatic aberration of magnification
(CC) at the telephoto end.
[0250] In the following the values of the terms in conditional
expressions (1) to (16), and (A) and (B) are presented for the each
of the examples. Some examples lack the values of some terms due to
the lack of a feature(s) (or component(s)) associated with the
corresponding conditional expressions.
TABLE-US-00009 Example1 Example2 Example3 Example4 (1)
f.sub.t/f.sub.w 38.43 28.79 38.43 28.79 (2)
arctan(IH.sub.MAX/f.sub.w) 40.3 42.4 42.4 42.4 (3) TL.sub.t/f.sub.t
0.542 0.596 0.527 0.596 (4) .nu.d(L1) 81.54 94.93 81.54 81.54 (4)
.nu.d(L3) 94.93 68.63 81.54 81.54 (4) .nu.d(L4) 94.93 -- -- -- (5)
d.sub.P1P/D.sub.1P 0.291 0.459 0.488 0.468 (6) .nu.d.sub.N2N 81.54
64.14 64.14 64.14 (7) f.sub.1P/f.sub.t 0.244 0.291 0.239 0.306 (8)
f.sub.1N/f.sub.t -0.032 -0.043 -0.032 -0.044 (9) f.sub.2P/f.sub.t
0.066 0.075 0.064 0.077 (10)f.sub.2N/f.sub.t -0.155 -0.11 -0.155
-0.113 (11)f.sub.3P/f.sub.t 0.111 0.127 0.117 0.125
(12)D.sub.1P/TL.sub.w 0.184 0.145 0.169 0.134 (13)D.sub.1P/D.sub.1N
2.108 1.433 1.878 1.398 (14)(TL.sub.t - TL.sub.w)/TL.sub.w 0.678
0.467 0.64 0.467 (15)ME.sub.1Pw/ME.sub.1Nw 2.628 2.172 2.61 2.159
(16)SF.sub.1 -0.962 -0.648 -0.822 -0.858 (16)SF.sub.2 -1.232 -1.235
-1.34 -1.609 (16)SF.sub.3 -1.515 -- -- -- (A), (B) S.sub.1P 4 3 3 3
(A), (B) S.sub.1N 3 3 3 3 (A), (B) S.sub.2P 3 3 3 3 (A), (B)
S.sub.2N 1 1 1 1 (A), (B) S.sub.3P 1 1 1 1 Example5 Example6
Example7 Example8 (1) f.sub.t/f.sub.w 38.43 38.43 38.43 38.43 (2)
arctan(IH.sub.MAX/f.sub.w) 42.4 42.4 42.4 42.4 (3) TL.sub.t/f.sub.t
0.53 0.545 0.544 0.543 (4) .nu.d(L1) 81.54 81.54 81.54 81.54 (4)
.nu.d(L3) 90.28 94.93 94.93 94.93 (4) .nu.d(L4) 90.28 94.93 94.93
94.93 (5) d.sub.P1P/D.sub.1P 0.307 0.298 0.294 0.294 (6)
.nu.d.sub.N2N 64.14 81.54 81.54 81.54 (7) f.sub.1P/f.sub.t 0.236
0.246 0.247 0.247 (8) .sub.1N/f.sub.t -0.031 -0.032 -0.032 -0.031
(9) f.sub.2P/f.sub.t 0.064 0.068 0.065 0.065 (10)f.sub.2N/f.sub.t
-0.151 -0.164 -0.147 -0.148 (11)f.sub.3P/f.sub.t 0.114 0.111 0.109
0.109 (12)D.sub.1P/TL.sub.w 0.185 0.192 0.18 0.181
(13)D.sub.1P/D.sub.1N 2.074 2.262 2.09 2.074 (14)TL.sub.t -
TL.sub.w)/TL.sub.w 0.649 0.609 0.66 0.67 (15)ME.sub.1Pw/ME.sub.1Nw
2.675 2.764 2.624 2.611 (16)SF.sub.1 -0.862 -0.963 -0.962 -0.962
(16)SF.sub.2 -1.274 -1.151 -1.223 -1.232 (16)SF.sub.3 -1.639 -1.526
-1.597 -1.59 (A), (B) S.sub.1P 4 4 4 4 (A), (B) S.sub.1N 3 3 3 3
(A), (B) S.sub.2P 3 3 3 3 (A), (B) S.sub.2N 1 1 1 2 (A), (B)
S.sub.3P 1 1 2 2
[0251] The distance to the object (or working distance) in the
state in which the zoom lens is focused on an object at a close
distance (first extremely close distance) is presented below for
each of the examples.
TABLE-US-00010 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Wide angle end 150 150 150
150 Intermediate 2 600 400 600 400 Telephoto end 1800 800 1800 800
Ex. 5 Ex. 6 Ex. 7 Ex. 8 Wide angle end 150 150 150 150 Intermediate
2 600 400 500 500 Telephoto end 1800 800 1000 1000
[0252] The amount of movement of the fourth lens unit for focusing
from an object at infinity to an object at an extremely close
distance (first extremely close distance) is presented below for
each of the examples. The fourth lens unit moves toward the image
side for focusing. The amount of movement of the fourth lens unit
has positive values, because movement from the object side to the
image side is represented by a positive value.
TABLE-US-00011 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Wide angle end 0.222 0.102
0.198 0.108 Intermediate 2 2.438 1.026 1.272 1.016 Telephoto end
6.847 5.108 5.393 5.846 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Wide angle end
0.191 0.221 0.197 0.199 Intermediate 2 1.938 3.409 2.586 2.545
Telephoto end 5.774 22.678 13.659 13.962
[0253] FIG. 17 is a cross sectional view of a compact camera 1 as
an image pickup apparatus using a zoom lens according to the
present invention and a small CCD or CMOS sensor as an image pickup
element. A taking lens system 2 is housed in the lens barrel of the
compact camera 1, and an image pickup surface 4 and a rear monitor
5 are arranged in the body.
[0254] The lens barrel may be provided with a mount portion, with
which the taking lens system. 2 can be detachably mounted on the
body of a single lens mirror-less camera. The mount portion may be,
for example, a screw mount or a bayonet mount.
[0255] As the taking lens system 2 of the compact camera 1, a zoom
lens according to the present invention, for example, a zoom lens
according to one of the first to eighth examples is used.
[0256] FIGS. 18 and 19 schematically show the construction of an
image pickup apparatus according to the present invention which is
equipped with a zoom lens as a taking optical system 41. FIG. 18 is
a front perspective view showing the outer appearance of a digital
camera 40 as the image pickup apparatus. FIG. 19 is a rear
perspective view of the digital camera 40.
[0257] The digital camera 40 according to this embodiment has the
taking optical system 41 arranged in the taking optical path 42, a
shutter release button 45, and a liquid crystal display monitor 47.
In response to depression of the shutter release button 45 provided
on the top of the digital camera 40, shooting through the taking
optical system 41, e.g. the zoom lens according to the first
example, is effected. Specifically, an image of an object is formed
by the taking optical system 41 on the image pickup element
(photoelectric conversion surface) provided in the vicinity of the
image plane. The image of the object picked up by the image pickup
element is processed by a processing unit and displayed as an
electronic image on the liquid crystal display monitor 47 provided
on the back of the camera. The picked-up electronic image can be
stored in a storage unit.
[0258] FIG. 20 is a block diagram showing the relevant internal
circuit of the digital camera 40. In the case described
hereinafter, the processing unit mentioned above includes, for
instance, a CDS/ADC section 24, a temporary storage memory 17, and
an image processing section 18, and the storage unit includes a
storage medium 19 for example.
[0259] As shown in FIG. 20, the digital camera 40 has an operating
section 12 and a control section 13 connected to the operating
section 12. The digital camera 40 also has an image pickup drive
circuit 16, the temporary storage memory 17, the image processing
section 18, the storage medium 19, a display section 20, and a
set-information storage memory section 21, which are connected to
control signal output ports of the control section 13 via buses 14
and 15.
[0260] The temporary storage memory 17, the image processing
section 18, the storage medium section 19, the display section 20,
and the set-information storage memory section 21 are configured to
be capable of mutually inputting and outputting data via a bus 22.
Moreover, a CCD 49 and the CDS/ADC section 24 are connected to the
image pickup drive circuit 16.
[0261] The operating section 12 is equipped with various entry
buttons and switches and notifies the control section 13 of event
information entered from outside (by a user of the camera) through
the entry buttons and switches. The control section 13 is a central
processing device such as a CPU and has a built-in program memory,
which is not shown in the drawings. The control section 13 performs
overall control of the digital camera 40 according to a program
stored in the program memory.
[0262] The CCD 49 is an image pickup element that is driven and
controlled by the image pickup drive circuit 16 to convert the
quantity of light of the object image formed through the taking
optical system 41 into an electrical signal on a pixel-by-pixel
basis and to output it to the CDS/ADC section 24.
[0263] The CDS/ADC section 24 is a circuit that amplifies the
electrical signals input from the CCD 49, performs
analog-to-digital conversion, and outputs to the temporary storage
memory 17 raw image data (or Bayer data, which will be hereinafter
referred to as "RAW data") that has undergone only amplification
and digital conversion.
[0264] The temporary storage memory 17 may include, for example, an
SDRAM, which serves as a buffer. The temporary storage memory 17 is
a memory device that temporarily stores the RAW data output from
the CDS/ADC section 24. The image processing section 18 is a
circuit that retrieves RAW data stored in the temporary storage
memory 17 or RAW data stored in the storage medium section 19 and
performs various electrical image processing including distortion
correction based on image quality parameters specified by the
control section 13.
[0265] The storage medium section 19 allows a detachable mounting
of a recording medium such as, for example, a card-type or
stick-type flash memory. The storage medium section 19 records or
writes RAW data transferred from the temporary storage memory 17
and image data having been processed in the image processing
section 18 in the flash memory to have the data stored in it.
[0266] The display section 20 includes the liquid-crystal display
monitor 47 and displays images based on picked-up RAW data, image
data, and operation menu etc. The set-information storage memory
section 21 includes a ROM section in which various image quality
parameters are stored in advance and a RAM section for storing
image quality parameters read out from the ROM section in response
to an entry(ies) made through the operating section 12.
[0267] The digital camera 40 having the above-described
construction uses as the taking optical system 41 the zoom lens
according to the present invention. Thus, the digital camera 40 can
be an image pickup apparatus that is small in size and easy to use
in various shooting situations while having a high zoom ratio or an
image pickup apparatus that is small in size and has an
advantageous design in performance wise.
[0268] As described in the foregoing, the present invention can
suitably applied to an image pickup apparatus that is small in size
and easy to use in various shooting situations while having a high
zoom ratio or an image pickup apparatus that is small in size and
has an advantageous design in performance wise. The zoom lens
according to the present invention can suitably used as an optical
system of such an image pickup apparatus.
* * * * *